|“The Mask of Hatred, a taste of invincibility! Too bad for you!”|
|— Harumi to Lloyd|
The Oni Mask of Hatred is one of the three Oni Masks. When worn, it will turn the user's entire body into invulnerable magma stone, making them invincible to all forms of damage.
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, with the Oni Mask of Hatred being sealed away within the Oni Temple deep within Primeval's Eye, presumably by the Oni themselves.
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 would later escape with her fellow Sons of Garmadon members with the three masks during the midst of the battle against the Sea Monster.
Ultra Violet uses the Oni Mask of Hatred to fend off the Ninjago police force during their attack on the Royal Palace, which was taken over by the Sons of Garmadon and coverted into the Temple of Resurrection. The Oni Mask of Hatred would later be used in the resurrection ritual with the other two masks. However, the Ninja would stop the ritual before it could be complete. The Ninjago police force soon arrives, arresting the Sons of Garmadon and presumably confiscating the masks.
At some point, the Oni Mask of Hatred would be recovered by the Sons of Garmadon. Harumi would use the mask 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 Mistaké gave them earlier to escape to the Realm of Oni and Dragons after Garmadon's Colossi 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.
- 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.
- Unlike the other two masks, the Oni Mask of Hatred will grow pigtails of black hair instead of horns like the other masks.
- So far, the Oni Mask of Hatred has appeared in three sets, while the other two masks appear in a total of two.
- The Oni Mask of Hatred is the only Oni Mask in the show which has had two different people use it; Harumi and Ultra Violet.
- While it is depicted that Ultra Violet uses the mask more often than Harumi, this isn't the case, as Harumi has used it more times than Ultra Violet, using it for some time in "Game of Masks" and for a good majority of "Big Trouble, Little Ninjago", while Ultra Violet only uses it briefly in "Dread on Arrival".
- During the ritual in "Dread on Arrival", the Oni Mask of Hatred is referred to as "Clotho-ha-eed" by Harumi.