|“Once one takes the Helmet of Shadows, the clock will start.”|
|— The Overlord|
The Helmet of Shadows is a piece of headgear. It gives the wearer control over the Stone Army, and served as the seal for the Celestial Clock. The helmet was likely created by the Overlord, who gave it to Lord Garmadon so he could control the Stone Army. After the Overlord betrayed Garmadon and possessed his body, the helmet was abandoned in Ninjago City before being claimed by Dareth, who put it on and gained control of the Stone Army. Dareth commanded the armored warriors to attack the Overlord, though following his defeat they were ultimately destroyed. Shortly after, the helmet was stored away in the Ninjago Museum of History.
When Kozu and several Stone Warriors were resurrected on the Day of the Departed, Dareth ran into the museum and found the helmet, putting it on once more and regaining control of the Stone Warriors. Dareth commanded them to beat up Kozu, which they did, returning his soul to the Departed Realm.
When Lord Garmadon arrived on the Island of Darkness, the Overlord guided him to the Celestial Clock and encouraged him to take the Helmet of Shadows, but warns that once the helmet is removed, the clock cannot be stopped unless the Helmet is returned. When Lord Garmadon put the helmet on his head, the hands of the Celestial Clock began moving once again, and the Overlord explained the significance of the artifacts to Lord Garmadon.
Seeking a way to stop the final battle, Misako notes that the scrolls say nothing about the Celestial Clock being halted, but is led to believe that the countdown will stop if the Helmet of Shadows was returned to its pedestal. Sneaking into Garmadon's camp as a prisoner "captured" by Stone Warriors, which are actually the Ninja in disguise, Misako managed to convince Garmadon to remove the helmet long enough for her to steal it and make her escape in the Earth Driller. As the Stone Army gave chase, Jay considered wearing the helmet, but was discouraged by the others, who suspected that its dark powers would corrupt any non-evil wearer.
When the Ninja reached the Celestial Clock, they searched for the helmet's pedestal. Unfamiliar with the clock's design, they were delayed long enough for General Kozu to arrive and reclaim the helmet. It changed hands repeatedly in the resulting scuffle, only for Misako to finally spot the pedestal. Unfortunately, she replaced the helmet a second too late to stop the countdown, forcing the Ninja to fall back as the Stone Army kidnapped Nya.
The Stone Army returned the Helmet of Shadows to Lord Garmadon, along with the captured Nya. Garmadon was wearing the Helmet once again when he began piloting the Garmatron to attack Ninjago. When the Overlord possessed Garmadon's body, he continued to wear the Helmet.
The Helmet of Shadows fell from the Overlord's head during his metamorphosis into his true form, and the villain left it in the streets of Ninjago City. This would prove fortunate for the heroes, as the Helmet would be donned by Dareth, and Misako was able to explain its function in time for the self-proclaimed "Brown Ninja" to save the Ninja from the Stone Army. Dareth then used his new headgear to send the Stone Army against the Overlord, buying enough time for the Ninja to begin ascending the dark dragon's tower.
At some point, the helmet wound up stored away in the Ninjago Museum of History, though it wasn't actually put on display—likely due to its feared and dangerous capabilities.
On the Day of the Departed, the people of Ninjago commemorated their fallen ancestors and spent time with their families. The Royal Blacksmiths put on a performance, during which the four members each wore a replica of the Helmet of Shadows, in commemoration of the final battle.
At the time of the performance, several of the Ninjas' old enemies were resurrected by Yang, including Kozu and several Stone Warriors. Kozu confronted Dareth, who he held responsible for the second defeat of The Overlord.
As a terrified Dareth ran into the museum, he found the Helmet of Shadows and once again used it to control the Stone Warriors, who turned on Kozu and beat him up. As a result, Kozu's spirit was sent back to the Departed Realm.
An artifact created by the Overlord that grants the wearer the power to control the Stone Army. In addition, removing the helmet from its resting place starts the Celestial Clock, which begins a countdown to the final battle between good and evil. The only way to stop the countdown is to return the helmet to the Celestial Clock, where it belongs. Garmadon wears the helmet while in charge of the Stone Army, and later, it is worn by the Overlord. Lost in battle, the helmet is found by Dareth, who uses it to help the ninja overcome the Overlord.
- The Helmet of Shadows appears in 70606 Spinjitzu Training as an easter egg.
- The Helmet of Shadows appears in the set 70505 Temple of Light. However, it is not explicitly identified as such in any descriptions, and it appears as a pure black version of the Stone Warrior's helmet instead of its show appearance.
- Strangely, in "The Last Hope," the Ninja did not realize that the helmet could control the Stone Army until "Rise of the Spinjitzu Master." Also, the Stone Army does not become under Jay's control after he dons the helmet in "The Last Hope," whereas the helmet instantly reacts to Dareth when he puts it on in "Rise of the Spinjitzu Master" (although the fact that he was reacting to Misako's cry of "Wait!" may have had something to do with it).
- The Helmet of Shadows can be seen in Wu's teashop in the Realm of Shadows play.