The Oni Masks were three powerful masks created by the Oni. Each mask has a unique individual ability that is derived from the three Oni warlords. When performed in a ritual with all three masks, it can open a portal to the Departed Realm and resurrect one with Oni-blood by chanting an incantation and then naming the mental part of the person the performer of the ritual would like to resurrect. For the process to be completed, the spell must respectively be completed.
Following Garmadon's resurrection, the Sons of Garmadon continued to use the masks, using them to help enforce Garmadon's rule over Ninjago City. However, both the Oni Masks of Deception and Hatred were broken during the conflict with the Resistance. The fate of the final mask, the Oni Mask of Vengeance, remains with the other artifacts in Ninjago.
Prior to the series
At some point in time, the three Oni Masks were created in the Realm of Oni and Dragons by the Oni. They would eventually end up in the realm of Ninjago through unknown means, where they would be separated around the island.
Members of the Sons of Garmadon, lead by Mr. E, infiltrate Borg Tower, which housed the Oni Mask of Vengeance. The Sons of Garmadon proceed to escape the building with the mask after triggering an alarm, but they are suddenly caught in a battle with Lloyd. While the other Sons of Garmadon members were swiftly beaten, Mr. E manages to escape from Lloyd with the Oni Mask of Vengeance in tow.
Three days later, the full ninja team arrives and reunite at Borg Tower, where they meet Hutchins, who informs them about the Oni Masks and how they would give the user tremendous power if they were ever united. He also informs them that the Oni Mask of Deception is currently being guarded at the Royal Palace. The ninja are later assigned by the Royal Family to protect the Oni Mask of Deception from a potential Sons of Garmadon attack in the future.
As predicted, the Sons of Garmadon attack the Royal Palace in hopes of stealing the Oni Mask of Deception. While Ultra Violet and several other Sons of Garmadon members fend off against the defending Royal Guards, Mr. E rides his bike through the palace and eventually finds where the mask is located. However, the ninja corner him in front of the mask's display case. Unknown to the ninja, Mr. E brought along the Oni Mask of Vengeance and puts it on, where it gives Mr. E two additional arms and swords. Mr. E fights off the ninja, eventually knocking them down after utilizing the mask's power to use Jay's Lightning against them. As Mr. E claims the Oni Mask of Deception, Kai, in a last-ditch attempt to stop him, blasts a fireball at him, which ultimately shatters the Oni Mask of Deception in his hands.
However, it is revealed that the Oni Mask of Deception that was on display was a fake; Hutchins had hidden the real mask in the vaults below the palace and tasks Lloyd and Harumi with fleeing with it. However, they are soon chased down by Ultra Violet and a few Sons of Garmadon members, who manage to knock it out of Harumi's hands and claim it before Lloyd and Harumi can.
Mr. E uses the Oni Mask of Vengeance to fight the ninja while trying to escape. When fighting Lloyd, the latter manages to knock the mask of Mr. E's head, undoing the effects on him. However, Mr. E manages to escape with the mask with an undercover Zane, who saved him only to gain his trust.
Killow uses the Oni Mask of Deception to lift rocks into the air in an attempt to crush Zane during the bike race after finding out he was a spy, trying to make him lose the race. However, Zane manages to dodge all of his attacks, forcing Killow to escape with the mask while Mr. E fights Zane.
Killow uses the Oni Mask of Deception's telekinetic powers to create a bridge of rocks over a trench for the Sons of Garmadon to cross in order to reach the crashed Destiny's Bounty. After reaching the Bounty, Killow and Mr. E both put on the Oni Masks of Deception and Vengeance respectively, when confronting the ninja.
Lloyd and Harumi manage to locate the Oni Mask of Hatred within the Oni Temple. Harumi attempts to grab it, but a force makes it so she cannot. She then explains to Lloyd that someone with Oni blood can obtain the mask. After Lloyd takes the mask, he soon begins to question Harumi on how she knew that he was part Oni. After a moment of revelations, Lloyd discovers Harumi's true intentions and realizes that she is the Quiet One. A fight then ensues, with it ending with Lloyd throwing the Oni Mask of Hatred over the side of the platform. However, Harumi dives after it, catching it while she manages to use her knife to hold onto the side of the platform.
Armed with the Oni Mask of Hatred, Harumi puts it on, using its powers to jump back onto the platform. Lloyd questions what the mask did to her, where she reveals that it has made her invincible to all forms of damage. After a very brief fight, Harumi reveals to Lloyd that she wants him to feel the pain she has felt following the death of her parents by having Lord Garmadon destroy Lloyd. Harumi then proceeds to flee from the temple with the mask, utilizing her invincibility to destroy the temple in an effort to destroy Lloyd.
Harumi soon regroups with the Sons of Garmadon, where she takes off the Oni Mask of Hatred as Killow rejoices that they now have all three. Harumi then explains they have a ceremony to attend to, ordering the Sons of Garmadon to take the Destiny's Bounty. However, they are confronted by the ninja. Lloyd soon returns, and as the Sons of Garmadon surround the ninja, the beast Harumi and Lloyd saw earlier then appears. The ninja and Sons of Garmadon then fight the beast, with Mr. E and Killow utilizing the Oni Masks of Vengeance and Deception to help fight the beast. While the ninja are distracted by fighting the beast, Harumi orders her forces to retreat with the masks. As they get away with the Bounty, Lloyd attempts to stop them but is soon captured by Killow.
Killow and Ultra Violet use the Oni Masks of Deception and Hatred to fend off the Ninjago police force while Harumi and the other Sons of Garmadon members help finalize the Temple of Resurrection within the Royal Palace.
Later on, Mr. E, Killow, and Ultra Violet all place the three Oni Masks into position at the ceremony. The masks then levitate from their hands, floating in a triangle formation. As Harumi recites the ritual, the three masks light up, connecting each other with beams of energy, which soon creates a rift to the Departed Realm. Eventually, the ninja arrive to stop the resurrection of Lord Garmadon, where they are successful in rescuing Lloyd and Misako and preventing Harumi in finishing the ritual. The Ninjago police force soon arrives and arrests the Sons of Garmadon, and presumably confiscates the three masks. Despite this, however, the ninja were too late; Lord Garmadon was reborn.
At some point, the Oni Masks would be recovered by the Sons of Garmadon, although it is exactly unknown when and where they recovered them.
Harumi would use the Oni Mask of Hatred after she confronts the now powerless Lloyd and Toddler Wu on a rooftop. She would continue to chase Lloyd while using the mask's powers to her advantage. Eventually, Harumi confronts Lloyd on a monorail, but Lloyd was able to throw Toddler Wu to the ninja on the Bounty, who were then forced to use the Traveler's Tea that Mystake gave them earlier to escape to the Realm of Oni and Dragons after Garmadon's Colossus beast destroys the Bounty. After Lloyd escapes Harumi with Nya, Misako, and P.I.X.A.L. in the same fashion Mr. E did prior, Harumi takes off the mask while angrily looking towards Lloyd.
Mr. E utilizes the Oni Mask of Vengeance while confronting the leading members of the Resistance following the discovery of the ninja's survival.
During the Sons of Garmadon's surprise attack on the Resistance's headquarters, Harumi and Killow utilized the Oni Masks of Hatred and Deception respectively, effectively using their powers to help overpower the Elemental Masters.
After Harumi was captured by the remaining members of the Resistance, the Oni Mask of Hatred was discovered by Skylor and Mystake amongst Harumi's possessions. Skylor questions if Lloyd should use it as a substitute for his missing powers, but Mystake warns of the mask's dark powers. However, Lloyd simple throws the mask on the ground in front of Harumi, realizing that it would be part of her plan if they used the mask.
Once Harumi had managed to trick Dareth into freeing her, she reclaimed the mask offscreen.
As Skylor gains control over the Colossus, a small Sons of Garmadon team lead by Ultra Violet and Killow arrive in the streets to apprehend the remaining members of the Resistance. Ultra Violet puts on the Oni Mask of Hatred in order to combat the Colossus, but Sylor uses the massive creature to swat Ultra Violet across the city.
Furious, Killow proceeds to put on the Oni Mask of Deception and uses its telekinetic powers to levitate three cars in order to damage the Colossus. However, it simple pushes away the cars, causing them to fall and pin Killow onto the ground, knocking off the mask from his face causing to cracked. As he desperately reached out and grabbed it in his hand, the mask fell apart.
Ultra Violet was holding the Oni Mask of Hatred while calling for a ride when she soon discovers Lloyd, Nya, and Dareth escaping with an unconscious Skylor. Nya soon engages Ultra Violet in a fight, throwing her weapon at the mask, knocking it out of Ultra Violet's hand and onto the street. Ultra Violet soon overpowers Nya and is able to get the mask after Nya is pinned under a car. Just before Ultra Violet can finish off Nya with the mask, Lloyd and Dareth arrive in their armored vehicle, ramming into the invulnerable Ultra Violet and sending her flying into a brick wall.
As Lloyd and Dareth escape after helping Nya up, Ultra Violet emerges from the debris as the mask breaks apart, falling off of her face.
- Oni Mask of Vengeance (Red) - Turns the user into a master swordsman with two additional arms and gives the user the ability to catch and deflect other people's powers. This mask was kept in a secret compartment within Borg Tower before it was stolen by the Sons of Garmadon during "The Mask of Deception." It is the preferred mask of Mr. E. Ultra Violet used it in Season 9 intro, but she hadn't used it in Season 9, after Mr. E's death. It is the only mask that has not been destroyed so far and it is currently located in the Borg Tower vaults.
- Oni Mask of Deception (Orange) - Allows the user to control, move, and manipulate objects by using telekinesis. This mask was guarded by the Royal Family in the Royal Palace before Ultra Violet recovered it from Lloyd and Harumi's possession during "The Jade Princess." It is the preferred mask of Killow. It was destroyed by Skylor, while controlling the Colossus in episode "Saving Faith."
- Oni Mask of Hatred (Purple) - Turns the user's entire body into invulnerable magma stone and lava. This mask was hidden in the Oni Temple deep within Primeval's Eye before it was stolen from Lloyd by Harumi during "Game of Masks." It used by Harumi in "Game of Masks," "Big Trouble, Little Ninjago," and "The Gilded Path." Ultra Violet uses it in "Dread on Arrival," "Saving Faith," and "Lessons for a Master." In episode "Lessons for a Master," it was destroyed.
When all three are united together at the Temple of Resurrection, the user can call an individual with Oni blood (full-blooded or hybrid) back from the Departed Realm. In addition, hair from the Oni's wife, son, and brother is necessary to achieve the summoning. Harumi used them to resurrect Garmadon's evil, before his purified side.
- Regarding the idea behind the masks as the "collectibles" of a season, Tommy Andreasen explained, "We didn't want to do weapons yet again. So we looked to Bionicle with the mask. Cerim Manovi who used to work with Bionicle came up with that idea."
- The three generals of the Sons of Garmadon—Mr. E, Killow, and Ultra Violet—all have similar color schemes to the masks.
- Additionally, each general specializes in using the mask matching their color scheme.
- According to Hutchins, the three Oni Masks embody the three Oni warlords.
- Whenever an Oni Mask is in use, it will grow horns of sort from the top of the mask.
- Unlike the other two masks, the Oni Mask of Hatred will grow pigtails of black hair instead of horns like the Oni Masks of Vengeance and Deception.
- The masks will grant the wearer a demonic tone to their voice when worn.
- The eyes of the mask will also glow for a short time after a mask is put on.
- When the Oni Mask of Hatred is in use, the "armor" worn by the user will have elements to the outfit they were previously wearing.
- The Oni Mask of Deception is the only mask that doesn't alter the user's physical appearance.
- So far, the Oni Mask of Hatred has appeared in three sets, while the other two masks appear in a total of two.
- In the sets, the Oni Mask of Deception's print is erroneously mirrored.
- An official description in a magazine says that the masks can open a portal to the Cursed Realm. This is an error, as Garmadon was sent to the Departed Realm upon the Cursed Realm's destruction.
- "Dead Man's Squall" and "True Potential" are the only Season 8 episodes not to feature an Oni Mask.
- It is possible that those with Oni blood are the only ones who can be resurrected by the Oni Masks.
- The names of the masks seem to foreshadow Harumi's true nature.
- Harumi wanted vengeance against the ninja for her parents' deaths.
- Harumi deceived the ninja into believing she was their ally.
- Harumi hated the ninja for failing to save her family.
- The Oni Mask of Hatred is the only mask in the show which has had two people use it: Harumi and Ultra Violet.
- The Oni Mask of Vengeance was originally called the "Oni Mask of Revenge."
- It is revealed in Season 9 that despite the Oni Masks' powers, the masks themselves are fragile and can easily be destroyed after taking enough damage.
- Ironically, Mr. E died while his mask is intact, but Killow and Ultra Violet lived after their masks were destroyed.
- It is unknown what happened to the Oni Mask of Vengeance after Lord Garmadon's rule was brought to an end.
- The outer appearance of the Oni Temple resembles the Mask of Hatred, which is located inside.
- The Oni Masks not only work on normal humans, but can work on other sentient beings as well, as Mr. E, who was an android instead of a human, was able to master the Oni Mask of Vengeance's powers with ease.
- It seems that nothing notable would happen if someone wore all three masks at once.
- These are the first set of collectible items to have fewer than four items.
- The Oni Masks have similarities with the Oni Masks from Jackie Chan Adventures.
- There are ten Oni Masks in Jackie Chan Adventures, while Ninjago has three Oni Masks.
The images on Oni Masks need to be organized.