| Spoiler warning!|
This article contains plot details from Skybound.
|“As long as there's something worth fighting for, there's always a need for a Ninja. And we'll be ready!”|
|Weapon of choice||Sword of Fire|
Fire Elemental Blade
Fire Techno Blade
Golden Twin Katanas
|First Appearance||Way of the Ninja|
2258 Ninja Ambush
LEGO Battles: Ninjago
Kai: Ninja of Fire (book)
|Voiced by||Vincent Tong|
Kai is the Red Ninja of Fire, and Nya is his younger sister. He and his teammates were chosen by Sensei Wu to protect the Green Ninja. He was the last Ninja to join the team, obtain his Golden Weapon, and to unlock his True Potential.
Kai and his younger sister, Nya, continued to work as blacksmiths in their deceased father's shop, Four Weapons Blacksmith. Upon greeting a customer who is revealed to be a sensei requests for a ninja though Kai declines the offer which sets the old man off. Unbeknownst to the two blacksmiths, the Skulkin enters Ninjago to abduct Nya as ordered by their master Garmadon. The villains succeed in their quest; as a result to recover Nya, Kai becomes a ninja with the help of Wu and eventually learns Spinjitzu and discovers his three other teammates, with whom he embarks on many adventures with as they battle the Serpentine and other adversaries.
Kai later helped to fight against the Stone Army, a legion of indestructible warriors led by Garmadon and The Overlord. After Lloyd defeated the Overlord and his father was turned back to normal, peace resumed in Ninjago until Pythor returned, aiding the Overlord in becoming the Golden Master and commanding the Nindroid army. The ninja clashed with the robots, and in the end the Overlord was destroyed, but Zane's life was seemingly taken in the process - sending Kai, Cole and Jay off into other occupations, as they were saddened by the loss of their friend.
When Lloyd attempted to get the team back together, Kai was very reluctant, as were Jay and Cole, but when they found out that Zane is still alive, they joined together once more. The ninja, accompanied by Sensei Garmadon, journyed to Chen's Island to compete in the mysterious Tournament of Elements. When Chen's true plans unfolded, and all the competitors of the Tournament allied together, Ninjago was put in danger once more, but the threat was eliminated when Chen's army was defeated at the Corridor of Elders.
After his father's banishment to the Cursed Realm, Lloyd was looked after by Kai, who became an influence on him. Yet when Lloyd was posessed by Morro Kai was frantic to get their friend back, but he and the other Ninja finally rescue Lloyd in Grave Danger. As an army of ghosts were released from the Cursed Realm, the ninja battled Morro and his forces at Stiix before the Cursed Realm was destroyed upon The Preeminent's destruction.
Kai was born in Ignacia, the first son of a blacksmith who owned the Four Weapons shop. He and his younger sister, Nya, were raised in their father's craft. Unknown to either of them, their parents were the Elemental Masters of Fire and Water. When his father died, Kai took it upon himself to keep the family business going, vowing to surpass his father's smithing skills.
Becoming a Ninja
One day while working, Kai explained to Nya how to make a sword, but became too impatient and thus produced a disfigured weapon. He was quickly reminded to be patient by his sister, only to be interrupted as an old man arrived. Yet the potential costumer began voicing complaints concerning the lack of tools for Ninja, and Kai quickly shooed him away.
Shortly thereafter, Ignacia fell under attack by Samukai and his Skeleton army. Kai attempted to defend it with the samurai armor he made, though the it proved to be slow and clunky. While he manged to defeat several skeleton foot soldiers, he was quickly subdued by Samukai. Pinned down by his armor, Kai would have fallen victim to the Skulkin General had the old man - Sensei Wu - not returned and saved him. However, while they were preoccupied, the skeletons kidnapped Nya and escaped to the Underworld. The young blacksmith intended to go after them, but was told by Wu of the First Spinjitzu Master and his two sons who fought over the four Golden Weapons, explaining that an honest man - Kai's father - had been entrusted with the map to their resting places. He was advised by Wu to become a Ninja and Kai reluctantly agreed in the hopes of saving his sister.
Kai was taken to the Monastery of Spinjitzu in order to be trained as a Spinjitzu master so he could save his sister, and all of Ninjago. During his training, Kai had to learn patience and how to harness the "fire" inside of him. This training consisted of running a course before Sensei Wu finished his tea. Kai accomplished this after several days and attempts by knocking the teacup out of Sensei's hands when he was about halfway through the course with his wooden training sword. However, he was then told by Wu that he had one final test the next day and was advised to get some sleep.
Later that night, while Kai was pondering Sensei Wu's training and brushing his teeth, he was set upon by three black-suited ninja. Their fight took them out to the courtyard where the blacksmith activated the training course to even the odds. They were quickly stopped however by Wu, who revealed that the three ninja were his students as well. Wu then used Creation to give each of the Ninja a suit that matched their elemental properties, and pronounced Kai as the red Master of Fire. After Wu explained their purpose, he announced that they would now leave to claim the first Golden Weapon.
Once arriving at the Caves of Despair, Kai ran ahead of the other Ninja while Cole was still formulating a plan, intending to find the weapon himself. The others caught up to him at Samukai's watch tower, and after Zane stole the map, Kai raced ahead again. The other Ninja followed him and caught up to the Red Ninja once more as he was attempting to remove the boulder blocking to the entrance to the scythe's chamber. Jay then accidentally revealed their position to the skeleton army digging for the weapon, and they were soon in a battle. After Jay discovered the key to unlocking his Spinjitzu, Kai and the others were quick to follow. They used it to drive off the skeleton army, after which they discovered that they had a bigger problem in the form of the weapon's guardian, the Earth Dragon. Kai happened to be holding the Scythe at the time, and decided that the only way out was to use it, contrary to Sensei Wu's instructions. After escaping, Kai was strictly reprimanded by Sensei Wu, and they went onward toward the next weapon, The Shurikens of Ice.
While on their way to the Frozen Wasteland, the location of the Shurikens, Wu told the Ninja about the most powerful technique in Spinjitzu, the Tornado of Creation. Kai began to attempt it, but was stopped by Sensei Wu, who explained that it could have disastrous consequences if done incorrectly.
After they succeeded in finding the Shurikens, the Ninja ascended to the Floating Ruins for the Nunchucks then used Jay's gliders to descend into the Forest of Tranquility. There they made camp, but Kai was awoken in the middle of the night and lured to the Fire Temple by Garmadon who was holding Nya there. Kai was forced to remove the Sword of Fire from its pedestal to cut the chain and save his sister. He was then attacked and defeated by his own shadow under Garmadon's manipulation, but Sensei Wu arrived before the dark lord could claim the sword. Realizing it had just been a trap to lure them away from the other Ninja, the three attempted to escape but were stopped by the Fire Dragon. As a last resort, Wu sacrificed himself and ventured into the Underworld with the Sword of Fire. While his act kept the four Golden Weapons apart, Kai and Nya were still left in the hands of the Fire Dragon.
Luckily the Fire Dragon soon realized that they were simply trying to protect the weapons and by the time Cole, Jay, and Zane arrived, Kai and Nya had befriended the Dragon. As the dragons were able to cross over into the Underworld, Kai urged the other ninja to hop on though Cole, who feared dragons, pointed out that there wasn't enough room. This inspired Kai to have the Ninja befriend the other dragons and together they successfully crossed into the Underworld.
The ninja attempted to use the stalactites to sneak past the guards of the Skulkin fortress but accidentally grabbed onto the legs of a Spykor. Out of fear Kai and the others fell to the ground outside the fortress where they were quickly surrounded by Skulkin and spykors alike. With their options limited Jay suggested they perform the Tornado of Creation and the Ninja successfully performed the technique, turning the fortress into a ferris wheel. The Ninja descended into the throne room where Sensei Wu was dueling Samukai for the Golden Weapons, though Kai forbade the other Ninja to interfere as it was their sensei's fight. Wu was quickly defeated, though when Samukai took the Sword of Fire, a portal between dimensions was formed, allowing Garmadon to escape from the Underworld. Knowing that he would one day return, Kai took the Sword of Fire and vowed to protect the weapon.
Kai and the other Ninja returned to Four Weapons where they were reunited with Nya and assured the villagers they would be ready when Garmadon returned.
Ninjago at peace
Cole, Zane, Jay, and Kai were told to train by Sensei Wu, but instead opted to spend their time racing their dragons. After Jay won a race and began bragging about his skills, Kai and the others challenged him to another race over the forest and back, with the winner becoming "Dragon Master" for a month. Zane objected, feeling that the Ninja should be training, to which Kai replied that riding their dragons was a form of training.
As the race began, Kai and Zane flew their dragons over the clouds, where they briefly dueled each other with their dragons' elemental breath attacks. On the home stretch, they were all neck-and-neck, but Cole won when he "activated the turbo" - a roasted chicken dangled in front of his dragon's nose. Once the others landed, Kai congratulated Cole on the win, but said that they would get him the next day. When Cole reminded him that the winner was supposed to be "Dragon Master" for a month, Kai and the others denied ever agreeing to the bet.
After retrieving the Sword of Fire, Kai placed it on a stand above his bed. One night, Nuckal and Kruncha infiltrated the Monastery of Spinjitzu to steal the Golden Weapons from the sleeping Ninja. Although the theft went off without a hitch, Kai was awoken when the Skulkin Generals lost control of the weapons and accidentally activated the training course. Half-asleep, Kai went outside to shut the course off, irritably reminding Jay that he had to repair whatever flaw was causing it to turn itself on. With that, Kai went back to sleep, completely unaware of Kruncha and Nuckal's presence in the Monastery even as they returned the Golden Weapons and fled to blame each other for coming up with the plan.
The Fire Dragon, Flame, flew Kai and Nya to the Fire Temple, wanting to show them something. After dismounting the Dragon, Flame led Kai to a passage connecting Ninjago to the Underworld. Kai started planning what to do when the ground fell out from beneath him. Krazi alerted Wyplash, who sent several Skulkin after him. He disarmed his enemies, but they picked him up. Nya and Flame then shot a blast of heat scaring the Skulkin and sealing the passage.
Return of the Serpentine
With peace throughout Ninjago, Kai and the other Ninja fell out of training and instead spent their time playing video games. After a three hour marathon, they were interrupted by Wu who unplugged the TV, who encouraged them not to put off tomorrow what could be done that day and start training again to prepare for his brother's return to Ninjago. In response Kai reminded him of when they preformed the Tornado of Creation, but there Sensei informed them that they still needed to unlock their true potential.
At that moment, Nya rushed in bringing word that Garmadon was spotted in Jamanakai village. The out-of-shape Ninja then rushed out the door and down to the dragon pen where Kai mounted the Fire Dragon with the help of Nya.
Eager to get back in the fight, the Ninja raced each other to Jamanakai village, but upon arrival Kai argued with Jay who had arrived first. They were interrupted by the sound of evil laughter from the village and drawing their weapons, approached the village ready for battle. However,the Red Ninja was surprised to find that it was in fact Lloyd Garmadon, the dark lord's son, who was causing trouble by threatening to release the serpentine, an ancient race of snakes which once ruled Ninjago, unless they gave him candy. The Ninja tied him to the top of a sign and embarrassed him in front of the villagers as they mocked him by eating candy.
As they prepared to return to the monastery, Kai discovered the prophecy of the Green Ninja in Wu's bag which he had taken by mistake. Kai believed himself to be the Green Ninja as did the others so when they returned to the monastery, the four Spinjitzu masters challenged themselves to a tournament for the title. Kai faced off against Jay in the first round and won, thus moving on to the final round against Cole. However, the tournament ended when Kai lost control of the Sword of Fire and the Ninja were scolded by Sensei Wu.
Determined to be the Green Ninja, Kai and the others devoted themselves to training. They were soon ordered back to Jamanakai Village by Wu however as Lloyd had unleashed the Hypnobrai tribe of Serpentine. Kai once again mounted the Fire Dragon upon arriving at the village, met up with Nya. After discovering they would need the anti-venom from the General's staff to save the village, the Ninja split up and after a fight with the snakes, sent them retreating. After the villagers had been cured of their hypnotism, Kai presented Wu with the staff and apologized for their lazy behavior earlier. With a new threat now upon them, Kai and the others returned to the monastery determined to unlock the secrets of their Golden Weapons and to reach their True Potential.
One night Kai ventured into the monastery kitchen for a midnight snack only to find that Zane had consumed everything but the cheese.
In the days that followed, Kai devoted himself to training at the monastery, though one time while he was practicing Spinjitzu, Zane iced the course over causing Kai to slip. He complained about Zane's strange behavior to Jay and Cole, only to be approached by Sensei Wu who noted that brothers are often different. They were then interrupted by the arrival of the Mailman who had a fan letter for Kai with him.
That night Kai and the others gathered in the monastery's dining hall and was surprised to find Zane emerge from the kitchen wearing a pink apron. As Zane failed to find it amusing, Cole dumped a plate of food on Kai's head and shortly after a food fight broke out.
The next day the Ninja followed Zane to Lloyd's Treehouse Fortress which the Zane had discovered the night before. Determined to destroy it before it became operational, Kai and the other Ninja snuck onto it and destroyed its supports. arrived Kai and the others discovered Zane was orphaned. The next day Kai and the others went to Lloyd's tree-house which acted as a Hypnobrai base. They started destroying it, but a hypnotized Cole turned on them. Before long Sensei Wu came riding in on Flame playing an ancient flute, which cancelled the Serpentine's powers. The group returned to the Monastery on Flame and discovered the Serpentine had set fire to it. Zane asked Shard put the fire out but, the Monastery was beyond repair. Kai and the others verbally attacked Zane but Sensei Wu caught them reminding them that Zane was their team mate and had them apologize. But before they could, Zane flew off on Shard to follow the Falcon. Kai and the others ate around a fire until Nya noticed Zane entering the camp, at which point he led them to their new home, the Destiny's Bounty.
After arriving on the Destiny's Bounty, Sensei Wu makes the Ninja clean the area. They do and put all the trash and junk in bin outside. However, later Jay's parents, Ed and Edna, arrive to see Jay there. After some time however, Ed and Edna leave Destiny's Bounty and go back to their home, located in a junkyard. However, the Serpentine are there and attack Ed and Edna. When the Ninja arrive, they find that they are too late and the Fangpyre had bitten Jay's parents and infected them with venom. Kai and the other Ninja, however, are ambushed by the Fangpyre, who have turned the whole junkyard into a snake infected area. Kai and the others defeat the snakes and leave with Jay's parents. After getting Fangtom's staff, Nya used it to cure Ed and Edna's venom.
After discussing who is the Green Ninja, Kai and the other Ninja are forced to train by Sensei Wu as punishment for being distracted and not doing their work. Kai, along with the other Ninja, are confused by Sensei Wu's riddle, "What is the best way to defeat an enemy?" Kai fails the riddle along with the other Ninja and assume combat is what Wu was talking about. After training and trying to solve the riddle, it is revealed that a boarding school has been attacked by Lloyd and an unknown Serpentine member, later revealed to be Pythor. The Destiny's Bounty takes them there, where they drop through the roof of the building on an anchor. Kai and the others chase the panicking Lloyd through the building until they reach the top of the building. As Lloyd and Pythor reach the roof, Kai and the Ninja apprehend Lloyd but Pythor escapes, stealing Lloyd's map. Sensei Wu, however, influences Lloyd to be good while reading a moral to him.
Kai discovers that all of his high scores have been replaced by Lloyd who at the time blamed it on Cole. However, Lloyd had messed up the other Ninja's hobbies as well. Sensei Wu reveals that he put Lloyd up to it to teach the Ninja "the destructive power of rumors." After this turn of events, Nya reveals that she has located the Constrictai and Venomari tombs. Kai and Jay take the Venomari tomb while Zane and Cole take the Constrictai tomb. As they arrive, Kai looks around, but is intoxicated with Venomari venom and begins to see elves and gingerbread men attacking him. Jay attempts to protect him while Kai is trembling from the visions. Cole and Zane arrive but are followed by Pythor and the Constrictai. As the two tribes surround them, the Ninja believe they will not survive the next attack. Kai hallucinates that a rope is in front of him, only for an actual rope to appear moments later. Suddenly, Samurai X arrives in a robotic mech and scares away the Serpentine. However, the Samurai knocks them unconscious while the Destiny's Bounty saves them from the Toxic Bogs. Kai's hallucinations then begin to fade.
Kai offered the other Ninja a bet: whoever finds the identity of Samurai X, they are the best and the Green Ninja. He attempts to capture the Samurai when he finds her in the Forest of Tranquility but the Samurai quickly captures him in a net. Later, when it's his turn to look after Lloyd, he drops him off at an arcade, then leaves, hoping to find the Samurai. After Lloyd has been captured by the snakes, Kai, Cole, Zane, and Jay go looking for him at The Lost City of Ouroboros. The Ninja get trapped in a cage that Pythor set up knowing they would come. Pythor puts them up to the challenge of battling Samurai X. The Ninja realize they are no match for the Samurai so they perform the Tornado of Creation and stop the Samurai. Worried the Ninja might win, Pythor tilts the platform, revealing a gigantic hole. When the Ninja and the Samurai are about to fall, the Samurai reveals she hasn't really been fighting with them and she will get them out of there, making her suit fly away with the Ninja clinging to it. When the suit crashes into the desert, Kai gets thrown farther away from the suit than Cole, Jay, and Zane. Seeing the Samurai also crash near him he goes to investigate. He sees the Samurai take off her head gear and recognizes it as Nya and promises to keep the secret.
As the Ninja continued to train, they became capable of impressive feats; Kai was able to run across a long path of red-hot coals with no ill effects. Later, he timed Zane as the latter sat underwater, expressing bewilderment as his white-clad ally remained beneath the waves for over ten minutes. After Zane finally returned to the ship, Kai and the others began speculating that they had reached their full potential, but decided to ask Sensei Wu before they jumped to conclusions.
When Kai and the others found Sensei Wu, he was packing his things in preparation for a journey. Nonetheless. Kai presented the Ninja's question, learning that they had yet to reach their True Potential. The Ninja soon learn of how Lord Garmadon came to be and why it is important to defeat him. Sensei Wu departs while Kai and the others put posters up for Lloyd, who had been captured by the Serpentine. Once the four notice the Falcon, they begin to follow it through Ninjago, hoping it will lead them to a Fangblade. After chasing it for miles, Kai and the others begin succumbing to exhaustion, telling Zane to continue following the Falcon into a snowy woodland. The Ninja eventually pick themselves up and find Zane to be horrified by something he's uncovered, learning that Zane is an android. Kai and the others still accept him and don't seem bothered by the revelation. After leaving the area, creatures referred to as Treehorns attack the Ninja and Kai is defeated by one of the creatures. The queen emerges, but is swiftly frozen by Zane, who gains his True Potential. The four of them leave the area and return to the Destiny's Bounty to discover Sensei Wu had not returned from his errands.
While watching Nya explain the venom process of a Fangpyre, Jay tries to impress her with men's cologne but finds out that Kai and the others pranked him by giving Jay perfume, which Nya is allergic to. The Ninja find that a Fangblade is at an amusement park and prepare to go there to acquire it. Jay attempts to go on a date with Nya at the park but Kai warns him not to, telling him "to get his priorities straight." The Ninja discover a ride that has Serpentine activity near it. The Ninja discover the Serpentine excavating the Fangblade and Kai declares a fight. Kai gains the upper hand in the fight along with the others but a mistake on Zane's part causes them to get frozen from one of his attacks. Kai and the others escape their confinement and Jay is revealed to have gained his True Potential while Nya is discovered by all the other Ninja to be Samurai X. Kai brags that he is the first to have found out and therefore should be the Green Ninja, but the other Ninja claim to not remember ever discussing that.
The Ninja, upset at losing the Fangblade, brainstorm for where the next Fangblade would be. Cole brings up that he knew about a trophy called the Blade Cup that seemed to be a Fangblade that his father once won at a talent show. The Ninja go to Cole's father and disguise themselves as dancers as to not cause suspicion around Cole's dad. They discover the Blade Cup is located at a talent show and enter it. However, the Serpentine have also discovered the Fangblade's location and disguise themselves as people in the audience, judges, and performers. When Kai and the others are ready to perform on stage, they began using various dance moves while the Serpentine attack them. Kai defends himself from them while Cole defeats the others using the Triple Tiger Sashay. The Ninja win the talent show and Cole's father is proud that they won the trophy without cheating as the Serpentine tried to do. Pythor attacks and nearly kills Cole's father but Cole protects him and gains his True Potential while the Serpentine manage to steal the Fangblade, making Kai the only Ninja left to find his True Potential.
Sensei Wu returns and surprises them by bringing Lord Garmadon, who has now grown four arms. Kai attacks Garmadon but Sensei Wu reveals that he is helping them search for Lloyd and order the Ninja to respect him during their temporary alliance. Kai gets more skeptical about Lord Garmadon and at one point overhears a conversation about the Green Ninja between Nya and Sensei Wu. Lord Garmadon discovers Kai eavesdropping and the two fight, only to be broken up by Nya and Sensei Wu. Later on, Kai searches for the Golden Weapons and discovers Garmadon is holding them. Thinking he is stealing them, Kai battles Garmadon and "wins." However, Garmadon reveals that he allowed himself to be defeated, as he was only fetching the weapons for the Ninja since they were heading over to their destination; this was confirmed when Sensei Wu told Kai that he was the one who told Garmadon to fetch them. Realizing this, the other Ninja scold Kai for his foolishness, leaving him humiliated. Despite the situation taken care of, Kai still retains his suspicion towards Garmadon.
After discovering the Fangblade is located at the Fire Temple, the Ninja go there to get it and rescue Lloyd from the Serpentine. Garmadon fights his way to Lloyd and rescues him but Pythor still has the Fangblade. In a desperate move, Kai impales the Fangblade to the cave wall with his sword, enraging Pythor. In retaliation, the Constrictai cause the lava to rise in the temple. Lloyd falls onto a rock but the Fangblade begins to fall into the lava. Garmadon attempts to save Lloyd again, but is unable to reach him and the other Ninja force him to leave the erupting volcano, much to his discomfort. Kai chooses to save Lloyd while the Fangblade falls into the pit below them. Kai gains his true potential and realizes that he wasn't meant to become the Green Ninja, but to protect him. With that, he transports himself and Lloyd out of the erupting volcano and back to the Destiny's Bounty. After reuniting with Lloyd, Garmadon genuinely thanks Kai for saving Lloyd, who is then revealed as the Green Ninja. Upon realizing this, Kai expresses an empathetic face, seeing how complicated it would be for Lord Garmadon and his son to be fighting each other in the future for the sake of Ninjago.
The episode begins with the Ninja cornering Spitta and forcing him to give them information on Pythor's whereabouts. Spitta tells them that they are days behind him. Back aboard Destiny's Bounty, Lloyd suggests that while Pythor is away, they should go to the Serpentine's inner sanctum to retrieve the other three Fangblades. The Ninja quickly find the snakes inner sanctum hidden inside the Constrictai Tomb but Lloyd and Lord Garmadon stay behind. In the tomb, the Ninja attempt to defeat the snakes, but to no avail. The Ninja are quickly captured and are forced to contact Lloyd for help.
Lloyd and Garmadon get into an argument, resulting in Garmadon leaving and heading to the underworld. and Lloyd gets a message from Nya asking for reinforcements. Lloyd goes on his first mission as the Green Ninja. Kai attempts to escape, but is quickly recaptured by Pythor who now has all four Fangblades. The Serpentine want to celebrate with a Slither Pit tournament, which Pythor agrees to. Lloyd arrives but comically falls down right in front of Pythor. Just before he is captured, however, Garmadon arrives with the Skeleton Army who battle the snakes. Lloyd frees the Ninja from their cage, and together they steal the four Fangblades and go back to Destiny's Bounty where Lord Garmadon leaves, making Lloyd upset. The Ninja are having a party for Lloyd getting the Fangblades, but little do they know that Pythor is outside their very window, plotting revenge.
Unaware that Pythor has snuck aboard the Destiny's Bounty, the Ninja plan to throw the Fangblades into the volcano. This fails when Sensei Wu nearly falls off the deck and is left clinging to the side, only for Kai and the others to save him. Pythor sneaks behind them but Lloyd warns them of his presence. Before Kai and the others can react, Pythor escapes on a Rattlecopter with the Fangblades and takes control over a tour bus. Kai fights off Serpentine on the top of the bus but is nearly knocked onto the road. Eventually Sensei Wu detaches the engine from the rest of the train and confronts Pythor, much to Kai's dismay.
The bus crashes into the Lost City of Ouroboros, halting the Ninja's transportation. Fortunately, Lloyd arrives and takes them aboard the Destiny's Bounty. Just as Kai and the others attempt to save Sensei Wu, Pythor unleashes the Great Devourer.
After watching his mentor and Pythor get eaten by the Devourer, Kai quickly leads the Ninja and their allies back to the Destiny's Bounty, but the Devourer follows them and destroys their former home. As Jay begins to admit defeat, Kai inspires the team with some words of wisdom from Wu. The team then heads to Ed and Edna's junkyard on their vehicles. It is there that Kai reveals the blueprints for the Ultra Sonic Raider. While there they discover that the Great Devourer has followed them and they use the Tornado of Creation to build a machine out of all the scrap at the junkyard to defend themselves against it. The Ninja manage to drive it away from the area but Zane is injured during the conflict.
Realizing the serpent is heading to Ninjago City, Kai and the others follow it to its destination. While the creature begins destroying the city, the Ninja arrive and attack it. The fight is interrupted by the Ninja's Dragons returning as the Ultra Dragon. Kai and the others cheer their respective Dragon on until the Devourer gains the upside of the fight. Lord Garmadon arrives and alerts the Ninja that the only way to truly destroy the Devourer is to hit its weak spot with the Golden Weapons. Kai is reluctant to hand him the weapons but eventually agrees. Kai and the others lead the snake around the city, eventually trapping it. The Ninja watch as Garmadon jumps from a building and strikes the creature's head with the weapons, causing it to explode into a mass of green goo. Kai is annoyed that the Golden Weapons are no where to be seen, but rejoices when he discovers that Sensei Wu is alive. Victorious, the Ninja celebrate.
In the aftermath of the Devourer's defeat, Kai and his friends spent much time cleaning up the great serpent's venom from around the city.
Meanwhile, Garmadon appeared to have survived his fight with the Great Devourer, and showed up where the serpentine were gathering. He used the Golden Weapons to recreate the Destiny's Bounty in a dark image. This convinces them to join him except for Skales, Fangtom, Acidicus, and Skalidor who were angry that there Serpentine brothers would leave them for a non-Serpentine. As The Ninja adjusted to their reduced powers (thanks to the loss of their Golden Weapons), their thoughts turned to finding a new home and training Lloyd for the inevitable battle with Lord Garmadon. A local woman offered boarding in her hotel, but Kai balked at the state of the suite they could afford.
Deciding that they needed to live in comfort before they could properly train Lloyd, the Ninja opted for a lavish suite and took up jobs around the city to pay for the rent, with Kai taking up a job as an entertainer at children's parties. Jay became a pizza delivery man, and Cole got a job as a guard of a bank. Zane began his culinary career when he became a chef at a restaurant. Being occupied by their new jobs, the ninja had limited time to train Lloyd, but were too tired to train him. When Jay had to deliver a pizza to the middle of nowhere, he looks down into the sewer because it was the only thing around. He witnesses Fangtom, Acidicus, and Skalidor plotting to rob a bank. Skalidor complains about being hungry, and asks when the pizza will arrive. At that moment, Skales appears behind Jay and abducts him.
Kai and the other Ninja began to properly train Lloyd, though soon realized their apartment wasn't the most suitable place. Wu sent them out into the city to look for a better training ground and they soon found Grand Sensei Dareth's Mojo Dojo. There they asked the owner Dareth if they could share the space to which he agreed if one of them could best him in a fight. While Dareth was showing off all his animal styles, Kai used Spinjitzu to send him to the ground, thus winning the fight.
Following their first session training Lloyd in the dojo, the Ninja exited to find the city under attack by Captain Soto's pirates. The Ninja quickly boarded a bus and raced towards the boat. After stopping by Wong's Costume to disguise themselves as pirates, Kai and the others boarded the ship and confronted Soto's crew. After a brief fight and with the help of the Ninja, the pirates were eventually subdued.
Jay assisted in helping Lloyd use his Green Ninja power to light a light bulb at Dareth's Mojo Dojo. Despite the Ninjas' encouragement, Lloyd fails to light a light bulb and became mad. Just then, Nya rushed into the room carrying a letter stating that Lloyd's old school, Darkley's School for Bad Boys, has changed to Darkley's School for Great Children, and that they wanted to Lloyd to receive an honorary award of excellence.
Kai and the others flew on the Ultra Dragon to the school where they are locked inside a room and discover that the students there had set it all up to get revenge on Lloyd. After very careful thinking, Kai and the ninja escaped the 'prison' only to find that Garmadon had create evil duplicates of the Ninja, who had infiltrated the school and were attacking the students. The Ninja could not let the evil ninja hurt anyone, so they attacked their evil counterparts. They would have been defeated if it weren't for the students coming to the rescue and confusing the evil ninja, who let their guard down and were defeated.
Kai, along with the other Ninja, compete in the Ninjaball Run to win the prize of $500 in order to save Dareth's Mojo Dojo. The ninja race in the Ultra Sonic Raider. Lloyd flys on the Ultra Dragon so that they have a better chance of winning the race. They race through dangerous terrain, and eventually Lloyd and his dragon crash putting him out of the race.
Kai, along with the other Ninja are turned into kids by Lord Garmadon and are chased by the Grundal, and at the end of the episode he and the other Ninja returned to normal.
Lord Garmadon uses the Mega Weapon to go back in time and make it so that Lloyd would never become the green ninja. The ninja later find out about his plan and jump into the portal Garmadon created with his Mega Weapon to stop him. The ninja get back in time and fall through a portal. They find themselves in Ignacia, at the time Wu came to Kai's shop and even before Skulkins attacked the land. They catch old Wu and explained him about the situation. This time, skeletons didn't kidnap Nya and Kai from the past had no will to become a ninja. Wu then leads him and Nya to the monastery. The Ninja decided to dress like skeletons and kidnap Nya so past Kai can get a reason to become the ninja. They did that, and Garmadon took Nya to the Fire Temple. Present Kai reveals himself to his past self, and they work together to defeat Garmadon. They succeed by destroying the Mega Weapon and Kai, along with other Ninja, comes back safely.
Starts when the ninja are awoken by their alarm clock. Later, Kai helps to fight the Stone Warriors. One stone warrior keeps the ninja running away. They stop inside a large room and close the doors, and as the Stone Warrior begins to break it down Lloyd suddenly comes up with a plan and tells the Ninja to distract it, which Kai helps do.
Kai helped train Lloyd to fight without using his eyes in Dareth's dojo, but they were soon interrupted by a series of earthquakes. They halted their training to tune into the news and learned that the aftershocks were getting worse. Kai immediately blamed Garmadon, though Misako pointed out that the Dark Lord would never do anything to harm his son.
The Ninja began to patrol the city for danger and even save a woman who was trapped by the collapsing street. The city soon falls under attack by the Stone Army and Sensei Wu orders the Ninja to send everyone to the NGTV office tower where they can be evacuated by the Destiny's Bounty. The citizens all climb to the roof while the Ninja hold off the Stone Warriors using the Ultra Sonic Raider and the Ultra Dragon. Kai continues to help hold off the Stone Army.
The ninja sail to the dark island on the flightless Destiny's Bounty. Along the way they run into a storm and the ship-eating Starteeth. When the storm passes the ship, which now is missing a rudder and and has a hole in the side, the ship runs ashore on an island with a prison tower. When the ninja get to the top, Dr. Julien greets them and takes them in. Later, the ninja sail further to the island of Darkness.
The Ninja finally arrive on the Island of Darkness, where the Stone Army is preparing for the final battle. The Ninja learn that the Temple of Light is where they can receive their elemental powers. In order to do this, the ninja must use a medallion to find the temple. Later Jay was able to find the Temple of Light by aligning three lights with the holes in the medallion - the temple is at the top of the island's highest mountain.
With their new vehicles, the Ninja head for the Temple of Light, barely keeping ahead of the Stone Army. Inside the Temple, they find pictures on the walls depicting their journey from the past until the present. Further in is a great bell, hanging above a strange design on the floor bearing the Ninja's symbols. Realizing that it's the Instrument of Peace, Lloyd strikes it, causing a light to shine on him and beams of energy to reflect off crystals in the walls. Soon, the entire room is crisscrossed with beams, and one hits a pillar, making it glow brightly. At the foot of the pillar, Kai's armor transforms, and an Elemental Blade with the power of Fire appears in his hand as well as the other Ninja. As their swords manifest blades representing their respective elements, Lloyd rises into the air. The Ninja use their swords to send their elemental powers to Lloyd.
The Stone Army finally marches into the Temple, but the Ninja are more than ready for them - using their new elemental powers, they easily trounce the warriors. Kai beats up some soldiers within a ring of fire. Finally, Lloyd summons the power of the Golden Dragon, creating a brilliant light that frightens the remaining stone soldiers into retreat.
At the beach, Dr. Julien repairs the Falcon, while the Ninja celebrate their restored powers by shooting down coconuts. The party is interrupted by Sensei Wu, who chastises the Ninja for their unseemly mirth; they may have the power to defeat the Stone Army, but the Celestial Clock is still counting down to the final battle between light and darkness. At that, Misako reveals a way to at least delay the battle: if the Helmet of Shadows is returned to its pedestal, the countdown might stop long enough for them to gain an advantage. Risking everything, the Ninja disguise themselves as Stone Warriors and escort Misako to Lord Garmadon's camp. As General Kozu takes Misako to his master's tent, the disguised Ninja are put to work carrying Dark Matter to the superweapon. The weapon is surrounded by a wooden wall, but the Ninja notice one protruding detail - a very large cannon - and ponder what Garmadon plans to attack with it. Later the Ninja are, forcing them to fight their way back down to the entrance as Misako rejoins them.
The Ninja make their escape with Misako and Nya in the power drill, but the Stone Army pursues them until the Overlord reminds Lord Garmadon that the Ninja could turn the army against him if they don the Helmet. After a frantic chase that ends in the Power Drill being disabled momentarily, Garmadon goes for the kill, only for Lloyd to blast it with his powers. Lord Garmadon emerges from the wreckage, weakened and vulnerable; from the Power Drill, the Ninja encourage Lloyd to finish him off. Despite everything at stake, the Green Ninja is unable to strike the fatal blow, forcing him to jump aboard the Power Drill as the Ninja make their escape from the advancing Stone Army.
At the Celestial Clock, the Ninja meet with Sensei Wu and desperately look for the Helmet's pedestal with minutes to spare. As the Stone Army arrives, the Ninja find the pedestal and replace the Helmet, but it's one second too late; the countdown has ended and the final battle is upon them. As the clock fires a mighty energy flare inland, the Stone Army captures Nya and the Ninja are sent down into a crevasse. Surviving the fall, the Ninja head off to prepare for the final battle.
Kai returned with the other Ninja to the beach where the Bounty was hidden and met up with Dr. Julien. As Wu and Misako attempted to raise Lloyd's spirits to face his father in the final battle, Kai pledged his fire to the Green Ninja and prepared for battle.
The heroes set off to Garmadon's camp, intending to begin the final battle, but were surprised to find it deserted upon arrival. Misako quickly realized that the Stone Army intended to use the ultimate weapon on Ninjago to shift the balance and allow the Overlord to cross over, thus the Ninja followed the machine's tracks in the hopes of stopping it before it was fired.
As the Ninja ran, they recalled memories of their past adventures until they were ambushed by Nya, whom had been turned evil by Garmadon's Dark Matter. Kai urged Wu, Misako, and Lloyd to continue on ahead while he and the other Ninja fended Nya off.
While at first having a hard time stopping for for fear of injuring his sister, Kai quickly realized a way to trap Nya using their Elemental Powers, and before long they were on their way again.
The Ninja arrived at the beach in time to witness the Overlord take control of Garmadon's body, having fired enough Dark Matter into Ninjago to allow him to cross over. Reassuring Lloyd that they stood behind him, Kai and the other Ninja raced into battle to defeat the Stone Army. Kai used his Elemental Blade to cut one of the Stone Army's machines in half before commandeering one of Garmatron's cannons. As Lloyd faced the Overlord, Kai watched with the other Ninja as their comrade was defeated. The Overlord proceeded to open a portal to Ninjago, though it closed just as the Red Ninja attempted to pass through it.
Hitching a ride on Kai's Fire Robot, the Ninja returned to the Temple of Light, where they activated a hidden mechanism that revealed the Golden Mech. When Lloyd sat in the cockpit, his powers as the Chosen One restored the ancient machine to fighting form. With the Ultra Dragon's arrival to the Island of Darkness, the group was able to return to Ninjago City, only to find it infected with Dark Matter and ruled by the Overlord, now restored to his monstrous true form. Despite their fighting prowess, the heroes were almost overwhelmed by the Stone Army, only to be saved when Dareth donned the Helmet of Shadows and took command of the ancient soldiers.
Kai and the other Ninja proceeded to ascend the tower but only to watch them fall victim to the Overlord's corruption. Later he distracts Nya and Lloyd was forced to limp up to the top of the tower alone, where the Overlord was waiting. In the aftermath of the Overlord's defeat, all of his creations and corruption vanished. Kai reunited with his allies in the crater left by the Garmatron's disappearance.
Following the defeat of the Overlord, Ninjago entered an era of peace. Without an enemy to fight, the Ninja were no longer needed and thus began teaching at Sensei Wu's Academy. At one point, Kai was caught on video by Jay singing in the shower.
During break on a rather stressful day, Nya approached Kai and the other Ninja and informed them they had received clearance for a field trip to Borg Industries. This didn't interest the Red Ninja who believed people should be learning from the past instead of wasting time on new technology, though he boarded the bus anyway.
Upon arriving at Borg Tower, Kai became stuck between the automatic doors, freeing himself just in time to board the elevator with the other Ninja as Cyrus Borg had requested to see them personally. After being introduced to the inventor, Kai questioned why the tower had been built atop where the Overlord had been defeated. Borg then presented them with a statue of himself as a gift for the Ninja, but promptly pulled Kai aside and ordered the Red Ninja to protect "them" with his life.
As the Ninja left with the statue, they accidentally dropped it and discovered new gis and the Techno Blades inside. Suddenly a robotic security voice in the elevator says that they should drop the blades. The Ninja refuse, and the elevator drops toward the ground at high speed. The Ninja luckily escape into an elevator going up right next to it, and manage to get their new outfits on for battle in their escape from Borg Tower.
When they get down of the tower, Sensei Wu takes the Techno Blades and says that he wants Kai and Zane in the air. Kai jumps on Zane's copter and hacks an enemy airplane, making it the Kai Fighter and reaching the outer space. While he was flying, Cyrus Borg gives him a visual message saying that few weeks ago they discovered that new virus, Digital Overlord, in the industries' system. He also says that they have to bring the Techno Blades out of the city, because if he finds out that they have them, he will never let them leave. After that, Kai gets into the sky fight with virus controlled planes. In the moment they almost get destructed, Lloyd comes on the Golden Dragon, defeating the robots. As the Ninja get back into the vehicles and get on the road outside of the city, Overlord spots that Wu is getting away with the Techno Blades so he sends two copters which capture him on the building roof. However before that happened, Wu quickly dropped Techno Blades into Kai's Fighter so the Ninjas could safely get them out of the city, while Wu gets captured by Overlord's forces.
After escaping from New Ninjago City, the Ninja are hides their vehicles. Misako then greets them and shows them to the Monastery, but Zane offers stay behind with the Techno Blades, as Garmadon (whom is now "Sensei Garmadon,") forbids any weapons in his monastery. As night falls, Garmadon arrives and teaches the Ninja and his students about "the art of the silent fist." While everyone inside is practicing the technique, Zane catches P.I.X.A.L. and tie her up, then returns to the Monastery as the Ninja come out to see what is going on. Zane then uses his Techno Blade to hack P.I.X.A.L.'s systems, freeing her from the Overlord's control. Grateful to Zane for saving her, P.I.X.A.L. tells the Ninja of Sensei Wu.
Suddenly, P.I.X.A.L. realizes she did not come alone and Nindroids surround the place. The Ninja successfully defeat the Nindroids by trapping them into mill wheel which then roll out. However, General Cryptor destroys the Ninja's vehicles. After that, the Ninja decides to split. Jay, Zane, Cole, Kai, and Nya gets an idea to shut down the power in the city to stop virus controlling machines in the land. As night falls, they arrive to the station, but with high guard of Nindroids. They manage to get inside but can't find the way to break the power charge. When Cryptor sends Nindroids inside, Kai remembers Garmadon's lesson of fighting without fighting so they decide to lure Nindroids to destroy the charge which then explodes and all the power disappears, including P.I.X.A.L. who gets shut down.Ed & Edna's Scrap N Junk to look for parts that would enable Zane's hover-copter to run on solar power. While Ed, Jay, Cole, and Kai search through the junk piles, Nya transfers half of Zane's power source to P.I.X.A.L.. Unbeknownst to the Ninja, Techno Wu arrives via hover-copter and powers General Cryptor, along with a few Nindroid Warriors, using electrocobrai. After activating a few Nindroids, Min-Droid sneaks and gets access to Ed & Edna's crane. The tiny droid uses the crane and launches the truck at a garbage pile.
Kai realizes and quickly informs his friends; the Ninja perform Spinjitzu and get out of the fallen vehicle, while Ed and Edna escape using bubble jet-packs. Meanwhile Jay and Cole are captured, Kai battles Wu clanging their weapons against one another. Eventually Wu manages to fling Kai away. Nya frees Jay and Cole and they assists Kai. However, Wu traps the Ninja in a corner, but Zane and P.I.X.A.L. come with a magnified vehicle and pick up Wu since he is now part metal. The Ninja are excited, but quickly ends when the Stranger frees Wu and flies away with their via hover-copter. However, the Stranger leaves a scale behind. Nya decides to give Lloyd and Garmadon a message.
The Hover-copter was eventually converted to solar power, the Ninja returned to New Ninjago City with Nya and P.I.X.A.L. There, they reunited with Borg and explained their suspicions as to who stole the hard-drive containing the Overlord.
They eventually came across the Stone Army Tomb, only to find the seal had been opened. Upon confronting Skales, they learned that the Serpentine had reformed and the Snake King even had a son. The Ninja and Nya were lead to a campfire where Acidicus told them of the Curse of the Golden Master, and how they believed it was referring to Lloyd. While the Ninja discussed the curse, Nya expressed her confusion that if the Serpentine didn't take the hard-drive, who was the culprit.
Both questions had to be put on hold though, as Nindroids suddenly attacked the place, and Kai ordered the other Ninja and Nya to protect the Serpentine. The ninja finds out that the Electrocobrai are their power source. Skales tells them at the Curse of the Golden Master is upon them, and says that they would not be able to assist the Ninja because they're choosing to stay out of the conflict. The Ninja then return to the surface.Digiverse, a digital world where they will be able to gain access to the Tower's central computer and fight the Overlord directly. When Jay points out that the hard drive is still missing, Borg explains the device will "download" the ninja themselves, along with the Techno-Blades, into the computer where the Overlord dwells. He also explains that this is the only method to succeed, as it will be a matter of time before the digital Overlord fully drains Lloyd's power. Although apprehensive, the Ninja are "downloaded" successfully, and they wake up in the Digiverse. In no time, they begin mastering the advantages of the digital world, except for Kai. the ninjas begin their trek down toward the Tower's central computer--ironically below the Tower, where the Overlord had been defeated years before. When the Overlord realizes they are close to him, he attempts to immobilize them, but fails due to P.I.X.A.L. electronically interfering from outside. He then turns the digitized New Ninjago City upside down, but the ninja keep moving with their digitized vehicles. Kai almost died when he tries to jump off the digital Borg Tower because his vehicle disappeared, but gets rescued by Zane. Together they get to the top--that is, the bottom--of the tower and insert the Techno-Blades... only to find the Overlord severed the circuit to the motherboard.
The ninja are severely beaten by the Overlord as he consumes more of Lloyd's golden power, proclaiming his becoming a true "golden master" of the real world and the digital world. Strengthened by Lloyd's proclamations that the ninja always have each other's strengths to fight together, ninjas fights off the Overlord's influence and turns gold and, using Lloyd's shared power, reroute the circuit to the motherboard and completely destroy the Overlord virus from the system, initiating a reboot.
At The Temple of Light, Lloyd gives up his Golden Power to restore the Ninjas' elemental powers. Meanwhile, at Borg Tower, Sensei Wu spots General Cryptor aboard a train heading for Ouroborus. going through a road near where Kai is.
Kai stands in a gas station flirting with a girl, when P.I.X.A.L. calls him and tells about the Nindroids approaching. He jumps into his Prototype X-1 machine car and heads to the highway. When he comes to the bridge, he accidentally fires rockets to the sky which got spotted by Pythor who was driving in a leading fuel truck with General Cryptor. He then launches Nindroid flyers to hunt him and destroy his car.
Kai successfully repels their attack, but Cryptor fires rockets at a hill above them and soon rocks that got separated from the hill fall down to his car. They block the road, but Kai and P.I.X.A.L. destroy them with rockets. To hunt down General Cryptor's truck, P.I.X.A.L. activates his interception bike which Kai is unable to control so he bumps into edge of the oil tank. He gets up to its roof and fights Nindroids, using his new fire power and Spinjitzu. This proves to be a mistake as he realizes that his fire power lit up the oil tank and that its going to explode. Soon they got to a tunnel, where the Min-Droid attacks him. The X-1 machine, remotely driven by P.I.X.A.L, accidentally scrapes an oil tank so gas starts leaking. It soon gets to flame from the sparks of the Min-Droid fighting Kai. When the fire comes to the leaking tank, the whole tank explodes but Kai jumps off to Pythor's truck and saves himself. He stays beneath his truck and hears Pythor talking to the Overlord by a radio. He tells people in Borg Industries that the Overlord is alive, but gets captured by Pythor who takes him to the lost city of Ouroboros.
By the time Zane, Cole, Jay, and Lloyd get to Ouroborus, they don't find anything new around until a huge door below them opens and they fall into an underground base where they find a huge rocket called "Arcturus." They realize that the rocket will lead Pythor and his Nindroid minions to space and reach the Golden Weapons from the star where the Mega Weapon was destroyed. Lloyd tries to stop him from lifting the rocket but Overborg stops him. With help from a freed Kai, the other ninjas hold off the Nindroids with their new elemental powers. Pythor initiates the countdown for the rocket to launch into space, so Lloyd leads the ninja into it just in time.
The Ninja put the space suits just as the rocket disengages its un-needed engines. However when they climb up toward the door leading to the cockpit they are attacked by Nindroids, who fire on them with laser guns.
Following Jay's initiative of going commando and learning that their Spinjitzu does not work in zero-gravity, the others take the laser guns too so they successfully repel the attack. Soon the Arcturus enters an incoming comet's tail and is battered by massive ice meteorites.
The Arcturus rocket crashes on the comet's surface where the melted and fused forms of the Golden Weapons are located. The Nindroids and the hidden Ninja discover them as Jay excitedly finds an extraterrestrial beetle. Unfortunately, said bugs eat anything metal—a fact that reaches them from Nya too late. While the Nindroids get away with the golden mass aboard their ROV, the Ninja follow pursuit in their own while using the pursuing bugs against their robotic adversaries. The Ninja eventually succeed in taking Cryptor's ignition key to the rocket, so that they cannot leave the comet with the Golden Weapons and take them to the Overlord.
However, their victory is short-lived when they find another bug swarm among the rocket—chewed up in pieces. Seeing this as well, Cryptor and the other surviving Nindroids use their built-in boosters to fly off the comet with their golden prize. Stranded on the surface with the insects, the Ninja report to the others that they had failed and are not coming back home.
In space, the Ninja despair after repeated failed attempts to escape. However, Lloyd refuses to give up, suggesting that they use their elemental powers and everything around them to restart the ship. Heartened by Lloyd's words, the Ninja repair the ship and use Zane as a power source. Though Zane gets overheated by the strain, they manage to fly back to the Earth—to land safely, the Ninja uses a new technique: Elemental Shields.
P.I.X.A.L. uses a motorcycle to catch up with her friends, using her power to land them on their vehicles. As the Ninja reunite with their allies, Cyrus tells them that they should head for The Temple of Fortitude, a place where the Overlord and the First Spinjitzu Master battled long ago. He claims there's a shield at the place, so the Nindroids won't harm them, and there is something he wants to give them that may help them save the world.
The Ninja begin travelling to the temple, but pause when they see the Golden Master's path of destruction. Lloyd reminds his friends that the only way to save Ninjago is to reach the Temple of Fortitude, but the Overlord sees them and uses a massive Spinjitzu tornado against them. The Ninja swiftly run back, rendezvousing with Cyrus, Wu, and Garmadon. There Cyrus gives them the ultimate weapon—a pill. Borg then explains that it was no ordinary pill, it could make anyone shrink. Garmadon and Wu decides to would hit the pill straight into the Overlord's mouth. Borg gives the Ninja armor which protects them from some attacks from the Overlord.
The Ninja go into Ninjago City, when an item hurls at them but are protected since they have on the armor. Wu hits the pill, which heads straight to the Overlord's mouth, but Pythor sacrifices himself and swallows the pill instead. As a result, Pythor shrinks down to the size of a worm. The Golden Master is outraged that the Ninja try to shrink him. He obtains the Ninja with his Golden Power only to miss Zane. The Ninja of Ice tells his friends to support him one last time, and the Ninja bounce him. Although, during the process, he landed and touched the Golden Master's gold. He refused to let go, admitting the fact that Ninja never quit, which frees his friends. He remembers his past, and freezes the Overlord which also killed him and the Golden Master. The Ninja are disappointed that Zane has passed, and proceed to his funeral.
Borg makes a speech on how he thought technology was the best way to destroy problems, but instead cost more. He now names Zane the Titanium Ninja and passes the microphone to Kai. The Red Ninja claims no one knew what powered Zane, and he thought it was brotherhood, because that's how Zane powered him. Saying that ninja never get forgotten, Kai says no matter where Zane is, he'll always be part of the team. When he finished his speech, snow began to appear.
After Zane's sacrifice the team has split up. Kai is now wrestling in underground Slither Pit as "The Red Shogun." As he sips some juice, Lloyd arrives and asks Kai to return. Like his friends, Kai refuses, saying Lloyd doesn't need a team and wishing it was him who gave his life instead of Zane. Lloyd reminds him he always wants to be the one, using his obsession of becoming the Green Ninja as an example before telling him to think about someone other than himself. Lloyd goes away telling Kai the same thing he did to his other teammates.
Kai goes to the park to see the statue of the Titanium Ninja as well as the Falcon before deciding to take up Lloyd's offer. However, Kai wasn't the only one to meet the Green Ninja at Chen's Noodle place. His other friends, Jay and Cole, had also been convinced and has met Lloyd there too. Lloyd informs the Ninja his new plan: hiring a new Ninja. The others completely dislike the idea, saying Zane is not replaceable. They quickly get interrupted by Eyezor and his gang.
The Ninja go to the back of the shop after they've stopped Eyezor's gang and see a drawn picture of Zane attached to a shrine with an invitation to a Tournament of Elements. They decide to accept and are walking onto the ship when Garmadon comes and tries to stop them, warning them that Master Chen, who invited them, is a dangerous man. Lloyd retorts by saying that they have to find Zane. Against the better judgement of Clouse, Chen's ex-second-in-command, Garmadon accompanies the Ninja on board, where they meet the other Elemental Masters.
While on board, Kai begins to take an interest in Skylor and questions Garmadon on what her element is, but he didn't know as he'd never seen her before. Soon enough, Kai sees Karlof, the Master of Metal trying to take Skylor's cloak and begins to insult him until the two begin fighting all over the ship. Just as Karlof pinned Kai and was about to finish the fight, Clouse calls it off: Skylor helps Kai to his feet and copies his powers without him noticing. Clouse announces that they reach Chen's Island, and while the Ninja wonder where they will find Zane, we discover that Chen is keeping the new Zane in a prison cell.
The contestants of the Tournament of Elements finally reach Chen's Island, rushing to be the first to see and go into Chen's place. The boat sets dock, allowing the people to escape the ship. The Ninja group together, while Kai loses conscious staring at . Kai immediately blocks the Ninja's path, telling them that "Girls go first." The heroes of Ninjago reach the underground fortress located in the island. Clouse arrives, commanding the contestants to welcome Master Chen. Master Chen brings his servants to welcome each contestant to their room. The Master of Fire enters his room first. His earliest discovery was his Kai poster. He wanders into his patio curiously, and glances at a familiar figure, who is also his neighbor: a ninja girl clad in an orange ninja gi. Kai attempts to introduce himself and use his Elemental power to win her over, but the girl--Skylor, by name--throws him off by flirting back, making him quickly lose control of the fireball in his hand. His reaction to the burning seems to amuse her.
Master Chen announces the competition starts now. Kai and Skylor see a Jadeblade on top of their roof. Skylor preforms back flips to get to the location of the blade. Kai jumps up too, and accidentally knocks her down. He managed to grab her leg, stopping her from falling. He flings her up; however, she reaches the blade, now making only one Jadeblade left and Karlof heads to the last one. Kai realizes and follows Karlof. Kai's archenemy won the battle, but before Karlof could hand it in, Kai unscrewed his Metal fist, getting a chance to win. Kai flies to Chen's location putting the blade in its spot to win.
Since Karlof has lost the contest, he is sent to Chen's secret location in the dungeon. Kai suggest they have a meeting later in his room. The Ninja had entered Kai's room with the exception of Jay since Skylor has arrived, therefore making the Red Ninja push Jay. After Skylor had re-entered her room, Kai helps Jay get up, apologizing for the mishap. The Ninja discuss the tournament while Cole lays down on Kai's bed, accidentally triggering a button again which reveals a secret entrance. Cole informs his friends, and they silently travel to the secret room. In the secret cave, Kai, Jay, Lloyd, and Cole hear Skylor shout in her room. They observe her room with little peeking holes, and surprisingly find her using the Fire element, which makes Cole tease the Red Ninja by singing that "Kai's heart is on fire." Soon, the Ninja face Chen's minions, but silently hide behind a rock while defeating the four minions. After they defeat the minions, they take their outfits to blend in and look like Anacondrai Cultists, and go to Chen.
Master Chen blurts out that they have captured Karlof, and steals his power with his Staff. The Ninjas' identities are revealed. Lloyd commands the Ninja to run out of the place; Cole trips on a booby trap which sets out traps and a huge snake. Running away from Clouse's snake, they finally make it back into Kai's room. They now promise to stay within the rules until they find Zane.
At Chen's island, the Tournament of Elements is on break. All the competitors are in the cafeteria eating lunch. The Ninja are still shaken up from Chen stealing Karlof's powers and try to come up with a new plan to find Zane. Chen then announces the six masters competing to get the jade blade next. The masters consist of Griffin Turner, Gravis, Ash, Bolobo, Neuro, and Kai.The match between Kai and Ash takes place on a bridge over a volcano, with the jadeblade and the competitors on a wooden bridge. Kai goes straight for the blade, but Ash flips the bridge over, causing it to fall on a rock below. Kai climbs under the bridge and attempts to kick Ash, but the master of smoke uses his powers to evade the attack. Kai continuously attacks Ash, with none of his blow landing while Ash keeps disappearing and reappearing and his punches landing, eventually sending the master of fire through the bridge and hanging. Kai initially struggles to hang on to the plank worrying Skylor, but he flips himself back onto secured planks and uses his Spinjitzu to push Ash back though the end result is the same. Lloyd encourages him to use his powers, so Kai then launches multiple fireballs, only for Ash to dodge them while they begin burning through the bridge. As Kai and Ash's battle continues, Clouse attempts to use his Magic though Chen prevents him from doing so. Ash manages to apprehend Kai, but he launches one more fireball which successfully burns through the last of the bridge, sending both of them onto the rocks below. The two then battle in midair over the Jadeblade where they're evenly matched until Ash makes for the blade. Kai then attacks him, where he uses his powers to avoid being hit: Kai uses this to take the blade and end the match with Ash eliminated.
Soon, most of the contestants are looking at the brackets and when the ninja see for themselves, they're shocked to find Cole and Jay have been set up to fight next. The Ninja confront Clouse about this, but he brushes it off. Kai suggests they ask Neuro for help, but he denies as helping them might hurt his chances in the tournament. Lloyd manages to convince him by letting him read his mind and seeing what happened to Karlof. Later Neuro tells Kai what he discovered: Clouse has a spell book where the page marked 149 has a spell that requires everyone's powers, though he couldn't find a way to stop the fight.
During the battle Jay tells Cole to take the Jadeblade as he himself is lucky to still be in the tournament, which he does, but throws it to Jay like a true friend, saying he should have backed down with Nya before telling the Blue Ninja to win it all. Cole loses, though Garmadon tells Kai, Lloyd and Neuro that he did the right thing.
Kai is seen running around outside the temples, appearing to be lost. He then runs inside one upon hearing Chen's voice announcing the next fight. Inside, Skylor is about to fight Jacob, the Master of Sound and they begin to smash vases in order to find a Jadeblade. Kai soon arrives and makes his way to his seat, stepping on everyone's toes in the process, soon realizes Skylor's fighting just as she sets Jacob's sitar on fire, while Jay fills Garmadon in on his crush on her until they found out they might be related. Garmadon explains that Skylor's element isn't Fire—it's Amber, meaning she can absorb other elements with a single touch, which immediately brings Kai's feelings back. After Jacob is eliminated, Chen announces he initially wanted to give everyone jewels for their work in the Tournament, though due to Jay's fight with Cole yesterday, he rejects the idea and takes away everyone's rooms, forcing them to sleep in the dining hall. As Jay and Kai berate each other while the other competitors leave, Garmadon warns them that if they don't make friends with the others, they'll try to eliminate them by any means necessary. While the competitors rest, the remaining three ninja discuss a plan but quickly jump back to their beds just as Clouse arrives. He orders Master Chen’s servants to add roller-skates to everyone’s feet, making the contestants curious. Clouse only says Lloyd will fight Chamille, Master of Form before leaving. Lloyd is confused as to who Chamille is, to which Kai seemingly explains how she can disguise herself to find another's weaknesses. Lloyd points out his only weakness is his aching back, but as Kai skates away, he appears on the other side, struggling to balance on his skates. Lloyd soon realizes that Chamille, disguised as Kai, tricked him into pointing out his only weakness to her.
During the Thunderblade Race, Skylor asks Kai what's left from stopping him from winning the tournament if Lloyd was out, to which he says he doesn't think of it before she knocks him down. By now, Lloyd and Chamille have each gained a point and have caught up to the others, who stop Lloyd from passing. Jay decides to make an opening by shocking Neuro, which works and stops everyone else: however, the plan fails as Kai accidentally knocks into Lloyd, causing him to fall behind by one point. Chamille orders Shadow to hit Lloyd's back, succeeding and making him drop his Jadeblade. Invizable then takes it, only for Jay to take it back and knock him off the track. Everyone does whatever they can to stop the ninja (with only Kai taking the hits), with Chen even releasing a buggy to extend Chamille's lead. Skylor comes up to Kai, saying he's convincing and Lloyd will soon be eliminated. With the score now 8 to 5, Kai decides to help despite not keeping balanced and uses his powers to hit Chamille and making her drop her blade, allowing Jay to take it. Skylor attempts to berate Kai for what he did, though he snaps and says that as ninja they stick together, causing Skylor to regret trusting him. Jay approaches him and informs him of Lloyd's progress though Kai now realizes Garmadon was right about not trusting the others. He then states if everyone knew about Chen's true intentions, they'd help: Chamille then takes back her Jadeblade. Kai latches onto Skylor, explaining what he meant and revealing the real nature of the tournament: upon mentioning the spell, Invizable, Shade, and Griffin become interested, and are convinced upon Neuro's testimony. Chamille attacks Kai and he lands near the buggy, allowing him and Skylor to take it. They drive up to Lloyd and let him take it, where it transforms into his color. After Lloyd wins, Chen refuses to have the event count, claiming Lloyd cheated and is disqualified, though Griffin stands up for the green ninja and states Chen is the one who cheated, where the master claims what his rules says, goes. Invizable, Kai, and Jay protest if Lloyd's out, then so are they whereas Skylor states if everyone is eliminated, there is no tournament. With that along with Clouse confirming it, Chen is forced to comply and eliminates Chamille. As everyone cheers for Lloyd, Skylor warns Kai that because of this, Chen will do anything to eliminate the ninja. Kai then states that as long as everyone sticks together, there's always hope.
As it turns out, the banquet is being held for the 8 remaining competitors who have made it to the second round. Chen tells the remaining eight that he knows that they have a secret alliance and that that the tournament is about stealing everyone's powers. To crumble the alliance, Chen lies and tells that whoever wins gets his staff of elements. Nya goes to the banquet and tells the Ninja that she's undercover and that one person in their group is a spy.
Later in Kai's quarter, all the fighters try to determine who the spy is. Garmadon suggests checking their backs and the one who has a snake tattoo on their back is a spy. Eventually, it comes down to Shadow and Skylor, the latter attempting to get Kai on her side by saying he didn't trust her: he stated he did and wanted the others to trust her, too. Before she did, Shadow made his escape declaring he wasn't the spy or the ninja's friend, so the ninja and the remaining masters assume Shadow is the spy. Kai tries to apologize to Skylor, but she refuses to listen and shows him and the ninja her back without a tattoo, leaving him guiltridden. Unbeknownst to them, Skylor truly was the spy and had hidden her tattoo using the power of Form.
For the next round of the tournament, Kai and the other remaining fighters boarded a blimp and were taken high above Chen's Island: while on the blimp, Kai argued with Shadow as everyone still considered him the spy. Once they were high above the island, Chen revealed to Kai's horror the the objective of the next round was to capture Nya, who had proof of Chen's plan. The masters were then dropped out of the blimp along with parachutes and Kai was successful in claiming one, though landed close of the island's volcano.
While searching for Nya, Kai noticed a rustling in the bushes and ignited his hand with a fireball only for it to be Skylor. The Master of Fire asked if she would help him in his search and the two set off together. However they had not gone far when they noticed a massive fireball across a pond. Kai began hoping from log to log to get across, but Skylor froze the pond to get there quicker, causing Kai to realize she was the spy. To his even greater surprise, she revealed that Chen was her father, who using the power of smoke, appeared beside them. Chen declared that Kai's time in the tournament was over and ordered Skylor to seize him, though Kai used his fire Spinjitzu to get to land. There however, Chen used his staff of elements to trap the master of fire in vines, capturing him. Kai was taken to the D.B. Express and thrown in the vengestone prison along with the other elemental fighters.
In the Anacondrai Temple, Kai, Jay, Griffin Turner, Neuro, Paleman, and Shade are being led in chains made of Vengestone to have their powers taken away. Upon being brought before Clouse and Skylor, Kai questions how she could help her father knowing he'll need her element for the spell. Saying she had no choice, Kai asks who planned to have him fall for her, which shocks Skylor. Chen raises his staff and takes the master's powers. Upon Chen ordering for the masters to be sent to the factory, Skylor begs for Kai to be spared saying he can help them which he complies with. Chen shows the Red Ninja his trophy collection (containing parts of the Ninjas' past adventures), though Kai responds that without the staff, he'd strike the villain down. Chen explains that unlike Kai and Skylor, who got her powers from her mother, he himself had no abilities and was told he'd amount to nothing. He then shows Kai a portrait of Arcturus and announces with Lloyd's power, he'd be unstoppable. He then tells Kai he knows he's still jealous Lloyd became the green ninja and offers to give him the power he wanted to try for so long. However, Kai refuses to betray his friends: Chen counters this by promising dark secrets about his parents his senseis never told him. Clouse comes to tell him of Lloyd initiating his plan soon and they leave Kai to consider his offer. After Lloyd sneaks into Chen's Palace and falls into another one of Chen's trapdoor into a cave made by Clouse's serpent. Kai appears and gets the green ninja out and advises him of the situation and plan, but Lloyd refuses and says he needs to face Chen. With that, Kai blows out his torch and leaves while Lloyd finds himself with Chen in the throne room. Shocked that Chen managed to turn Kai against him, Lloyd proceeds to battle while trying to talk some sense into Chen. However, the man uses everyone's elements to overwhelm the green ninja and defeats him.
Nya wakes up in the dungeon of the snake where, along with Garmadon, she's chained to a post. Chen, Clouse and Skylor approach and inform them of Lloyd's defeat and that his power will be taken soon. Nya questions how they were able to defeat him to which Kai enters, saying Lloyd never stood a chance alone. Garmadon, now enraged of Chen turning the ninja against each other like he did to their ancestors, grabs Skylor and threatens her unless he and Nya are released: they call his bluff due to his reform and he's forced to release the orange ninja, shocked with her father. Clouse opens a tunnel door for his snake to enter after its nap while Nya tries to talk sense into her brother. As everyone leaves, Kai winks at them, revealing he only pretended to switch sides to gain Chen's trust. As Chen and Clouse leave to prepare for the ceremony, Kai pulls Skylor back and explains he can get the staff. Skylor asks why he'd tell her after her betrayal: Kai states she let him go for a reason, with her feelings for him being the most obvious choice which she admits.
In the ceremony Lloyd questions why Kai would betray him, though he tells him not to worry. Chen then has Skylor give up her powers. By now, Skylor has completely lost her power and Chen proceeds to take Lloyd's Energy. As Clouse begins the spell, Kai tells Chen he forgot one more element: the "element of surprise." Skylor then kicks the Staff of Elements out of her father's hands and Kai uses it to free Lloyd, hold off the cultists and freeze Clouse. Lloyd tells him to destroy the staff, but Kai begins to become corrupted by its power. Just before he uses it on Lloyd and Skylor, everyone busts in and attack. Kai grabs the staff before Chen does and destroys it, restoring everyone's elements and captures the cultists. Chen, Clouse, Eyezor, Kapau, Chope, and Zugu escape with Skylor now their prisoner. With the elemental masters now in control of the island, Nya and Garmadon assure Kai they'll find them while Kai expresses surprise at finding an old friend and making new ones--including a new kind of friend in Skylor.
On Chen's Island, Lloyd comforts Kai about Skylor, saying that while she couldn't pick her family, she picked a good friend, with the addition of Cole saying with no other way off the island, they'll find them. Garmadon congratulates the five on bringing the elemental masters together and sticking together, though he warns them to keep their guard up. Later, Griffin Turner and Neuro inform the ninja, Nya and Garmadon that Chen plans to use Skylor's absorbed powers to finish the spell and turn the cultists into Anacondrai. Kai takes off on one of the crushers while Jay takes the mech, Garmadon and Cole take the Jet, Zane takes a buggy, Nya takes the DB Express and Lloyd leaves on his dragon. Later Skylor is now being chased by Eyezor and is saved by Kai, who crashes his chopper into the thug's own bike. Kai takes a rocketboard for himself and the chase begins again when Chen starts to pursue them in the bladecopter. Combining their Fire, they create a smokescreen which Chen flies through, sees Kai, and notices Skylor disappeared not seeing she used her Form to disguise herself. Kai emerges from one of the buildings, having alerted the team and takes an interest in exploring the town, but brushes it off to bring Skylor back. However, the two are ambushed by Kapau and Chope and captured in an Element-blocking net. Later in the crystal caves, the transformation is revealed to have begun, Kapau reciting the spell in Clouse's place. As Chope finishes the spell (Kapau having fainted from its effects), Kai urges Skylor to resist the transformation. However, the transformation is completed which Chen cheers for while. Kai attacks Kapau, Chope, and Chen though none of them are affected due to their thick Anacondrai skin. Skylor breaks free and attacks her father before he attacks Kai. Accepting her new form, the red ninja leads the two out of the cave and return to the coast riding Kai's Elemental Fire Dragon supporting his theory, convincing and encouraging everyone to unlock their dragons. Kai also states that although Chen brought them there so only one remained, he didn't think that together, they were one.
Kai and the other elemental masters are scattered all around Ninjago, after chasing down the decoy trucks. Nya attempts to contact them from the new Destiny's Bounty. Lloyd instructs Neuro to send a message to the other elemental masters ordering them to Nya's Samurai Cave, where she informs them that Chen has taken over the entire eastern coast. Wu points out that the Corridor of Elders will be the best place to make their final stand, and the elemental masters agree. The Ninja journey all over Ninjago to rally support from the citizens.
The Ninja, citizens, and Serpentine get to the Corridor and start the ultimate battle against Anacondrai. Pythor escapes Chen's camp riding a rat and carrying Chen's spell book. He gets to the battle and tells Lloyd to take him to his father because he knows the way to end the battle. Later, Lloyd opens the portal to the cursed realm and unleashes spirits of Arcturus and his troops who quickly curse Chen and his soldiers turning them into ghosts. They all get hovered into the portal, which then explodes. Later Kai ask Skylor to join the team but said that she has the noodle-business to run although she promised to Kai that she will keep in touch with him, when they almost kissed they get interrupted by Dareth. On the top of the corridor, the ninja, Wu, Misako, and Dareth sit around a fire on a broken statue, watching construction workers building statue of Garmadon in the corridor. Lloyd tells that today they will say goodbye to a legend and burns the book in the fire.
With Garmadon gone, Kai took Lloyd under his care and promised to watch over him. He and the Ninja used their Elemental Dragons to capture a Fangfish that had been terrorizing a local village, though Kai bragged that he once had caught one twice as big. Upon returning successful to Wu's new tea shop Steep Wisdom, Kai and the others were sent by their Sensei into Ninjago City to advertise the new store, yet without using their powers. While they obeyed their sensei at first, after failing to attract anyone Kai decided at use his elemental powers to create a teapot out of fire.
Unfortunately, Morro possessed Lloyd's body and the other Ninja lost their elemental abilities. They returned to Wu for answers just as the tea shop fell under attack by the Master of Wind. Kai attempted to help Lloyd regain control of his body, but was taken away by the Ninja as the fled in the Destiny's Bounty just as the Green Ninja was starting to regain control.
Morro soon caught up to them using his Elemental Dragon and while the masters of earth and lightning fended him off, Kai and Zane escorted Wu to their quarters for him to make an imprint of the staff's secret message. The ghost ninja crippled the flying vessel however and soon confronted Kai who was almost thrown out of the Bounty. He was saved by Zane, but the ship crashed in the Forest of Tranquility.
The Ninja made camp and Wu told them of his past with Morro. That night Kai dreamt of him promising to look after Lloyd, only for the Green Ninja to be eaten by a Fangfish. He was awoken by a walliper to find that Misako has arrived and discovered that the first symbol means Airjitzu, a martial art created by Sensei Yang, though discover that Ronin had recently stolen the only known scroll. The Ninja mount wallipers and Kai leads them towards Stiix where Ronin was keeping the scroll.
Unfortunately, their head start was lost when Kai lead them away from Stiix rather than towards it. After Zane pointed this out, Jay and Cole elected to follow Zane instead and they soon came across train tracks leading to Stiix.
After nightfall, they came to a train station and stopped, intending to rest. However, they were soon beset by Wrayth on the Chain Cycle and engulfed in a frenzied battle against the ghost menace. Incidentally, he defeated himself when his chain hooked on a nearby water tower and poured its contents onto himself. The Ninja were left stunned by this, but realizing that a passing train was headed to Stiix, quickly ran after it.
The Ninja eventually arrived in Stiix and confronted Ronin in his shop. The thief demanded a high price for the scrolls, but due to Kai's horrible negotiating skills, it was raised even higher. To earn money, the Ninja were hired to build a dock and Kai operated the crane. Unfortunately, a fly damaged the Titanium Ninja's language database and they ended up accidentally destroying the bridge. With Zane unable to speak, Jay took charge and decided that they should simply steal the scrolls.
When they did, however, Morro and his latest summoned partner Soul Archer had arrived at the shop for the scroll and summoned more ghosts. Using the Aeroblades, they got rid of the ghosts; unfortunately, Ronin called for R.E.X. and took the scroll but didn't get far thanks to Morro. Kai chased after Morro but failed to regain the scroll. In addition, Ronin offered to help Kai out of the strangle weed in exchange for something: Kai gave him everyone's business shares of Steep Wisdom. In return, Ronin told him of an alternate way to learn Airjitzu: Sensei Yang's Haunted Temple.
Kai began complaining about his new Deepstone suit because it was heavy, which he believed prevented him and the others from performing Airjitzu. Wu told him that it would protect him from turning into a ghost. Sometime later, Soul Archer shot him in his chest, but the Master of Fire didn't turn into a ghost.
Once they were nearing the highest peak of the Wailing Alps to beat Morro from reaching the Cloud Kingdom, Kai was the first to successfully do Airjitzu up to the top. He was then able to encourage Cole by telling him ghosts can't die, which helped him perform Airjiztu and allow them to beat Morro into the Blind Man's Eye.
Upon reaching the gates of Cloud Kingdom, Kai and the other Ninja were greeted by Fenwick. They were then shown inside the writing hall where the Ninja learned that the citizens of Cloud Kingdom were the writers of destiny.
Fenwick proceeded to inform the Ninja that Morro sought the Realm Crystal hidden in the tomb to unleash The Preeminent, before ushering them into a building filled with toys to meet the "master writer". They quickly discovered it to be a trapped as they had been locked away with Nimbus, a terrifying creature. With Cole's ghost abilities, the Ninja managed to escaped and discovered that Fenwick was actually working for Morro.
The Ninja soon ran into Nobu who informed them where the Sword of Sanctuary was kept, though the Ninja arrived just after Morro claimed the sword. With it in hand, the ghost was able to escape from Cloud Kingdom though after an intense chase down the Wailing Alps, the Ninja emerged victor with the sword in possession.
While Cole and Lloyd tried to infiltrate the Misfortune's Keep, Kai and Zane would be assigned to recover their ship, the Destiny's Bounty 2.0. However, after being attacked by the guard and his dog, the two of them were forced to leave. Later, after regrouping in Mezmo's Slither Pit and discussing their next plan of action, he would accompany his team in an attempt to defend New Ninjago City from the Sky Pirates. In an attempt to get the lantern with the map to Tiger Widow Island, he and Jay were separated by an explosive barrel thrown by Monkey Wretch. Before Jay could catch up, Nadakhan would teleport the both of them to the Island of Darkness. In an attempt to escape, Kai would wish to go back, only to be taken back in time to when his father was a humble blacksmith. After witnessing his father ask for his help, Kai, not wanting to mess with the timeline, demanded that Nadakhan would take him back to a time when the latter wasn't present, when his fangirls still appreciated him, etc. Because of the high content of his wish, Nadakhan instead chose to focus on a single aspect, transporting Kai into an alternate reality where all of the psychotic fangirls began chasing him around. In desperation, he was goaded into wishing it all away, resulting in his imprisonment in the Djinn Blade. As a result, Nadakhan would use the power of his soul to begin tearing chunks out of Ninjago.
Whilst trapped inside the Sword of Souls, Kai would be freed by Jay alongside the rest of his imprisoned allies, their release resulting in the defeat of several Sky Pirates converging on their position.
After thanking the members of Jay's new team, Kai went with the other ninja to stop Nadakhan from marrying Nya. However, they failed to stop the ceremony and retreated before Nadakhan could capture them. Regrouping on the Misfortune's Keep with the now reformed Dogshank and Flintlocke, they discovered from Jay not only where Clancee kept the Tiger Widow Venom but also the true reason behind the wishes Nadakhan granted: their inabilities was only interpretation on Nadakhan's part: in the end, Nadakhan's powers were limited in that he had to solely rely on his victims to accomplish his wishes, as the ability came from its rightful owner. With this, Flintlocke regained his aim and was declared the one to shoot Nadakhan with the venom while the others distract the Djinn.
The ninja put the plan into action, though discover Nya has been possessed by the now-revived Dilara: although they evade most of the attacks, Nadakhan turns them into gold statues until only Jay is left. Flintlocke is soon able to take the shot, successfully hitting Nadakhan and his power begins to diminish: unfortunately, the venom also hit Nya, who soon dies in Jay's arms. Everyone is devastated, Kai having to be comforted by Zane while the weakened Nadakhan musters up his remaining strength, though it's in vain as Jay wishes from the heart that Nya had taken his hand and that Nadakhan was never freed. Time soon reverses to when the ninja are on the roof of Ninjago City hospital with only Jay and Nya remembering all of the events. The two renew their relationship, which everyone is happy for, though Kai becomes disgusted from seeing his sister kiss Jay.
Typically preferring red attire, Kai has brown, spiky hair. He is often seen with a focused expression on his battle-scarred face, a slight notch visible on his left eyebrow. Since The Royal Blacksmiths, Kai's civilian attire consists of a red half zipped up sweater over a maroon shirt with his symbol on the chest and brown pants. Throughout season 6, he wore a red cap over his hair to conceal his identity.
For more images on Kai's appearance in his different ninja suits, click here.
Fittingly for his elemental affinity, Kai is very hotheaded, prone to taking action before he thinks things through. He is capable of making careful observations when the need arises, but his emotions often override his caution. His single-mindedness made interaction with his teammates difficult at first (especially due to his worry about Nya), but he eventually learned to work with the other Ninja. He can be arrogant at times, insisting that he is better than his peers and growing depressed when he seems to be lagging behind their training.
Later, following the ninjas' fame, Kai would end up getting something of a larger head and bigger ego, constantly flirting with girls and enjoying the merchandise styled after him. Likewise, he indulged in his fame the most out of all of the ninja.
Kai also has something of a stubborn side, believing that he is in the right until overwhelming evidence to the contrary is presented. This is especially pronounced during Lord Garmadon's stay on the Destiny's Bounty; Kai repeatedly accused the four-armed villain of treachery or plotting despite Garmadon's insistence that saving Lloyd was his primary concern at the time. On the other hand, Kai's stubborn streak lends him incredible determination that allows him to bolster the team's spirit in the face of impossible odds.
The most prevalent facet of Kai's personality is his dedication to people he cares about - if someone can earn his friendship, he will stop at nothing to protect them. Much of his stubbornness and recklessness are due to his desire to help his loved ones, either directly or by becoming strong enough to defeat anyone who might threaten them with their plans. In turn, his friends and family work to balance out Kai's more extreme traits, causing him to become a levelheaded mentor for Lloyd by the time he and his comrades begin training the Green Ninja.
Kai favors swords in combat, taking up a curved silver blade against the Skulkin when they attacked his shop. He used the Sword of Fire as his primary weapon until it was lost, and then switched to wielding regular katanas. He eventually gained an Elemental Blade that allowed him to harness his fire abilities to an even greater degree. A few years after Lloyd defeated the Overlord, Kai, along with the other three ninja (Cole, Jay, and Zane), receive Techno Blades, a weapon which allows the ninja to hack into any electronics. He also has an Aeroblade (along with Cole, Jay and Zane), that can destroy ghosts.
Kai is the ninja of Fire, and though he is a hero now, he came from humble beginnings. His father was a trusted ally of Sensei Wu and the two adventured together for many years. Wu would later hide the map showing the locations of the Four Weapons of Spinjitzu in his friend’s blacksmith shop. Kai was the last member recruited for the team by Sensei Wu and the last to achieve his full potential (which happened when he saved Lloyd from the belly of an active volcano!) He can be hot-headed and impatient, but is trying to control that.
- For the first two months of his life his parents called him Ash.
- Kai once by accident forged a weapon called a 'Swingana' … Part yo-yo, part sword. It was not a big success.
- When Kai uses his elemental power in a vehicle, it gets powered up and engulfed in flames … which is why flying a hang glider is a bad idea.
- Once Kai singed off his eyebrows with the sword of fire, but no one noticed because he painted it back on with a black marker.
- When Kai's sister, Nya, was a baby, he used to juggle hammers to entertain her. When he dropped one on his foot, she laughed the hardest.
- The name, Kai, means "strong," "victorious," and "recovery," in three Asian cultures, all of which fit his hotshot attitude in the Ninjas' battles. His name may also be derived from the Japanese word Akai, meaning "red."
- Kai is the last Ninja to join the team, the last to claim his Golden Weapon, the last to unlock his True Potential, and the last to have a love interest. On the other hand, he was the first Ninja introduced in the series, the first to tame his respective dragon and the first to perform Airjitzu.
- He appears to have a fear of Christmas-related themes, as shown in "Can of Worms," when the Venomari's venom causes him to see things like gingerbread men and elves.
- Since "The Invitation," Kai's had feelings for Skylor, which she initially used against him until she began to genuinely return them. It is possible they are currently still seeing each other.
- Kai and Nya's parents were the First Elemental Master of Fire and the First Elemental Master of Water.
- He inherited the elemental powers of his father, and Nya inherited her mother's.
- Kai is mentioned to be aquaphobic during "Stiix and Stones," or have an extreme fear of water. It is ironic, then, that his sister turned out to be the Elemental Master of Water.
- Kai was the first Ninja to be trapped in the Sword of Souls.
- Kai's official minifigure has scars on his face. In the show, Kai doesn't possess these scars.
- He considers Lloyd to be his best friend to the point of considering him to be a younger brother. As of Season 5, Kai also becomes somewhat of a father/guidance figure to Lloyd. This bond between the Red and Green Ninja can be traced to that of the same colors in Chinese mythology and culture.
- Kai's elemental symbol is the Chinese character "平", meaning "flat" or "peaceful."
- Kai appears to holster the Sword of Fire as if he was Left Handed, but uses all other weaponry and tools in his right hand; this might mean Kai is ambidextrous.
- Kai was the only Ninja that performed his True Potential only once and never use it again after unlocking it: currently though, Nya shares this fact with him.