Lloyd appeared in Jamanakai Village, throwing toy snakes at the residents and demanding their candy. When the Ninja arrived, they were surprised to see a boy instead of the fearsome Lord Garmadon, prompting Lloyd to explain that he was the dark lord's son. He threatened to unleash the Serpentine on the Ninja if they didn't surrender, but the unimpressed heroes hung him on a sign, where the irate villagers pelted him with fruit for his trickery.
Eventually, Lloyd escaped, swearing revenge on the Ninja. He ended up wandering into the icy Glacier Barrens, where he stumbled upon a strange tomb. Curious, Lloyd opened the tomb and fell inside, where he met the Hypnobrai, a tribe of real Serpentine. The Hypnobrai General, Slithraa, attempted to hypnotize Lloyd, but the would-be evil overlord slipped on the icy floor, causing Slithraa to stare at his own reflection in the ice. Thus hypnotized by his own attack, Slithraa accepted Lloyd as his master, and Lloyd immediately ordered the Hypnobrai to Jamanakai Village to take his revenge.
With the Serpentine at his side, Lloyd quickly subjugated the village, stealing all of its candy for himself as the Hypnobrai mesmerized the villagers. When the Ninja returned, Lloyd watched the battle until the Ninja managed to steal Slithraa's staff, prompting him to call a retreat.
Lloyd commanded the Hypnobrai to build him a Treehouse Fortress within Wildwood Forest, planning to use it as a base from where he can conquer the rest of Ninjago. However, the Ninja attacked and began cutting the support ropes, causing it to collapse. Lloyd ordered the Hypnobrai to fight back, but Skales betrayed him by dropping him into one of his own booby traps. With Lloyd as their prisoner, the Hypnobrai raided the Monastery of Spinjitzu and burnt it to the ground, reclaiming their staff in the process.
Back at the Hypnobrai Tomb, Lloyd tried to convince Slithraa to make the others free him. However, Skales defied his General's command, challenging him to a Slither Pit for leadership. During the fight, Lloyd found the Map of Dens in an ice crevice, and surrepitously pocketed it while cheering Slithraa on. Unfortunately for Lloyd, Skales' superior fighting skills allowed him to defeat Slithraa and become the new General. With his authority, Skales banished Lloyd from the tomb, forcing the would-be evil overlord to wander Ninjago once again.
When the Ninja moved into the Destiny's Bounty, Lloyd sadly looked on from a distant dune, glaring at his enemies before continuing his own journey.
Plotting revenge against the Hypnobrai, Lloyd decided to find another Serpentine tribe to ally with. He released the Fangpyre from the Fangpyre Tomb and requested their aid against the Hypnobrai. Although the General, Fangtom, was more than happy to agree, he admitted that they would need to bolster their forces to stand a chance against the Hypnobrai. To this end, the Fangpyre led Lloyd to Ed and Edna's junkyard, where they bit Ed, Edna, and several vehicles.
The next morning, Jay and the other Ninja arrived at Ed and Edna's Junkyard to visit Jay's parents, only to find the latter slowly transforming into snakes. Lloyd appeared with Fangtom atop a junk pile as the Fangpyre attacked the Ninja, laughing as the heroes were beset by the Fangpyre Wrecking Ball and the Fangpyre Robot. When Master Wu attempted to use the Sacred Flute against the Fangpyre, Lloyd used a Serpentine boom box to drown out the melody, brushing off his uncle's demands to turn down the music.
Despite this, the Ninja defeated the Fangpyre forces, prompting Lloyd to call yet another retreat. To his dismay, the Ninja created vehicles of their own from their Golden Weapons, allowing them to catch up to the Rattlecopter and retrieve the Fangpyre Staff to return Jay's parents to normal. When Lloyd led the rest of the Fangpyre against the Destiny's Bounty, the ship took flight and escaped, although not before accidentally dropping the Fangpyre Staff on Fang-Suei's head.
With the Fangpyre forces bolstered, Lloyd led the tribe against the Hypnobrai. Unfortunately, he was betrayed by Fangtom after the latter saw his old friend Skales in charge of the Hypnobrai, but he managed to sneak away while the Generals debated over what to do with him. Having overheard Skales' mention of the Anacondrai being the most powerful and fearsome tribe of all, Lloyd sought out the Anacondrai Tomb within the Sea of Sand.
Upon opening the tomb, Lloyd was greeted with a roomful of skeletons. The Anacondrai General, Pythor P. Chumsworth, appeared and explained that his tribemates had starved to death, and he was the last survivor. Although disappointed at the lack of minions, Lloyd asked Pythor to work for him against the other Serpentine, and the latter agreed, due to Lloyd releasing him from the tomb. The villainous duo proceeded to engage in several shenanigans around Ninjago (including stealing candy, trespassing on grass, and other mischief) before Pythor suggested attacking Darkley's as payback for Lloyd's expulsion.
Lloyd and Pythor proceeded to invade the former's former boarding school, holding his former classmates hostage and setting up booby traps for the Ninja. Despite this, the Ninja eventually cornered them on the roof, where Pythor showed his true colors and stole the Map of Dens. Lloyd protested this action, but Pythor mocked his attempt to control the Serpentine before vanishing from sight, leaving Lloyd to be apprehended by the Ninja.
With Lloyd in their captivity, the Ninja planned to give him a severe punishment, only for Master Wu to take a different approach: reading a book to Lloyd and welcoming him aboard the Destiny's Bounty. Although the Ninja questioned this course of action at first, they soon realized that Master Wu was trying to turn his nephew away from the dark path he had chosen to follow, and Lloyd soon agreed to work with his uncle against the forces of evil.
Though no longer actively attempting to be evil, Lloyd retained a mischievous streak, which he expressed by performing various tricks against the Ninja: beating all of Kai's high scores in Fist to Face 2 and blaming Cole; putting extra spices in Cole's Violet Berry Soup and claiming Jay was behind it; tinkering with Jay's Sparring Robot and saying Zane did it; and putting Kai's clothes in Zane's laundry, turning the latter's suit pink. He even stole Master Wu's lesson book, forcing the old master to improvise a lesson when he broke up the Ninja's argument. Before anything further could be done about Lloyd, Nya called the group to the bridge, revealing her findings on the locations of the remaining Serpentine tombs. While Cole and Zane investigated the Constrictai Tomb, and Kai and Jay went to search the Venomari Tomb, Lloyd was forced to stay on the ship and clean up the mess his pranks had left.
Unfortunately, the Ninja failed to stop Pythor from releasing the remaining Serpentine tribes, with Lloyd blaming himself for starting the trouble by unleashing the first three. Master Wu comforted him by reminding him that the past cannot be changed, only the future, and the Ninja subsequently redeployed when Serpentine activity was detected in Ninjago City.
After a successful mission to prevent Pythor from uniting the Serpentine tribes, the Ninja were eating dinner when Lloyd arrived, having finally washed the pink out of Zane's ninja suit. He apologized for his pranking and gave Cole a can of nuts, only for the Black Ninja to refuse, believing it to be another prank. In doing so, however, Cole ended up walking into Lloyd's real prank—a pack of rubber snakes in the fridge—and Lloyd joined the others in laughing at the success.
At the Destiny's Bounty, Lloyd is showing the Ninja how he would attack a Serpentine. The Ninja correct him excessively, and Lloyd asks Master Wu what the best way to defeat a Serpentine is. He tells the group that it was the Sacred Flute that Pythor stole, and that without it he is afraid that they will have a hard time fighting off the Serpentine. The alarm goes off and alerts the Ninja to Serpentine activity at the Mega Monster Amusement Park and Lloyd quickly offers to tag along, but Master Wu tells him to stay aboard the ship.
Later on Kai, who is patrolling Ninjago City for signs of Samurai X, drops Lloyd off at the Kiddie Arcade, much to Lloyd's protest. As Kai speeds off, Lloyd overhears the Serpentine being conviced to travel to the Lost City of Ouroboros. Lloyd dons a snake costume and follows the snakes on to a bus to the city. After a long drive, they reach the city, which is resting in the Sea of Sand. They all pile into a colosseum, where Pythor is announcing a Slither Pit. He tells the Serpentine that if he beats all the Generals at once, he wants their complete, undivided loyalty. Skales, who is secretly supporting Pythor, gives him the stolen Sacred Flute, which he uses during the fight. Lloyd notices this, yet continues to watch on regardless. Upon winning the fight, Pythor demands the Serpentine to bow, but Lloyd accidentally drops a part of his disguise in the process, alerting the Serpentine to his presence and allowing himself to be captured.
The Ninja, back at the Destiny's Bounty, are complaining about their failed attempts trying to capture the Samurai. Master Wu comes in, noting that Lloyd is not present. Kai tries to deflect the blame to Cole, who then tries to place it on Jay. Master Wu, who is utterly afraid of what might have become of his nephew, tells the Ninja to go find him. The Ninja begin to track down Lloyd, following security camera footage and footprints, and discover he has been captured at The Lost City of Ouroboros. Although they try to rescue him, they are forced to flee, leaving Lloyd behind with the Serpentine.
Lloyd was brought along when the Serpentine went to the Desert Pyramid in search of the second Silver Fangblade. Realizing that the pyramid is full of traps, Pythor forced Lloyd to find the Fangblade for him. Although Lloyd narrowly managed to make it to the center of the pyramid, he discovered that the Fangblade was missing. He reported this to the Serpentine, who presumably extracted him from the pyramid before continuing their hunt for the Fangblade.
Lloyd was brought along when the Serpentine discovered the third Fangblade in the volcano behind the Fire Temple. As Pythor excavated the artifact, the Ninja arrived, along with Lord Garmadon, who had allied with them in order to save his son. During the resulting battle, Pythor had a group of Constrictai burrow into the volcano to destabilize it, and the snakes carried Lloyd on their way out of the volcano. Before the Serpentine could escape, Lord Garmadon attacked them, successfully freeing Lloyd. Unfortunately, another tremor caused part of the ledge to crumble, leaving Lloyd stranded on a rock in the increasingly-unstable sea of lava.
As Lloyd floated on his perch, he saw Kai trying to retrieve the Fangblade as everyone else escaped. He begged Kai to help him, giving him a moment of indecision, but the Red Ninja eventually agreed, leaving the Fangblade to sink into the lava as he pulled Lloyd from the sinking stone. As the volcano erupted around them, Kai unlocked his True Potential at last, using his new abilities to shield himself and Lloyd as they flew back to the Destiny's Bounty.
Once the ship was safely away from the eruption, Lloyd was finally able to reunite with his father, who thanked Kai for the rescue. As Kai explained that he unlocked his True Potential by realizing his destiny was to protect, not become, the Green Ninja, the Golden Weapons began to glow. When held in front of Lloyd, the weapons floated in front of him and crackled with green lightning, revealing that Lloyd himself was the Green Ninja. Lloyd's surprised pleasure soon turned sour, however, as Lord Garmadon realized that this meant he would have to fight his own son in the final battle for control of Ninjago.
On the Destiny's Bounty, Lloyd discovers Lord Garmadon attempting to steal information on the Ninja while the group is out on a mission, and the two argue. The two are interrupted, however, when Nya attempts to call in, requesting reinforcements. Lord Garmadon attempts to answer her plea but Lloyd, in his frustration, tells his father that they don't need his help and to leave instead. Lloyd dresses up in his green ninja suit and sets out to help his friends.
Lloyd arrives at the Serpentine's Underground Fortress but is powerless to help his allies. Just before he is captured, however, Lord Garmadon arrives with the Skulkin Army who battle against the Serpentine. Lloyd frees the Ninja from their cage, and together they steal the four Fangblades and return back to Destiny's Bounty where Lord Garmadon departs, leaving Lloyd upset, but proud of his father.
During a storm on the way to Torchfire Mountain, Lloyd was training below deck on the Bounty when Pythor appears. He tied the struggling boy to the training equipment and duct taped his mouth shut. Lloyd eventually managed to free himself and warn the Ninja that Pythor was onboard, but by then, the Snake King had already hacked the ships system. Lloyd ran on deck to confront Pythor, who had by then taken the fang blades. Lloyd attempts to battle the snake, to which Pythor critiques his childish fighting skills. Lloyd explains, though, that he was only trying to distract him, and it is then that Nya in her Samurai suit arrives. The Serpentine general escapes, though, and Lloyd and Nya watch as he flies off on a Rattlecopter. Lloyd is told to stay on the Bounty while the others chase Pythor to the Lost City of Ouroboros, and he flies the ship there right behind them.
Lloyd and his friends bore witness as the Great Devourer rose from Ouroboros and began terrorizing Ninjago. After attempting to thwart it, they formed an unlikely alliance with Lloyd's father, who destroyed the Devourer with the Golden Weapons before departing with them. After finding Master Wu mercifully alive, Lloyd recognized that he would eventually have to face his father to save Ninjago, but was comforted by his friends.