Oni Masks originate from Japan and were created by good Chi wizards to seal Oni generals within. The masks were then scattered to the four corners of the Earth. Oni Masks can each summon a different tribe of Shadowkhan once the mask is attached to a host's face, but if all nine Masks are brought together in one location, the Oni spirits are set free, summoning enough Shadowkhan to engulf the Earth in eternal darkness. It is interesting to note that half of the masks accidentally fell on peoples faces (or were sat on in Ikazuki's case), three were put on willingly, one was never worn, and one was forced upon a face (Tarakudo).
Maroon Mask Worn by: Chow (accidentally)
Summons: Ninja Khan
The Ninja Khan are human-like in appearance and rely on speed and weaponry to dispose of enemies.
Purple Mask Worn by: Ratso (accidentally)
Summons: Razor Khan
Razor Khan possess sharp spikes and blades all along their bodies and are one of the fastest tribes of Shadowkhan, able to run fast enough to catch up with a speeding train.
Yellow Mask Worn by: Scruffy (accidentally)
Summons: Bat Kahn
Bat Khan have large wings and sharp talon like hands: also they have the ability to release dark chi magic as blasts of power and as chains.
Green Mask Worn by: Captain Black (accidentally)
Summons: Sumo Khan
Sumo Khan are very large and powerful, but slow and rely on their strength to defeat enemies.
Blue Mask (Ikazuki) Worn by: Finn on his rear because he sat on it (and animated by the rat talisman)
Summons: Samurai Khan
Samurai Khan wear heavy armor and carry deadly shadow swords.
Orange Mask Worn by: Paco (willingly)
Summons: Squid Khan
Squid Khan have four arms that can stretch to great lengths. They also have no legs and slither along the ground.
Yellow-Green Mask Worn by: Hak Foo (willingly)
Summons: Shadow Eaters
Start out small but grow to great sizes after devouring a person's dark chi through their shadow and putting them to sleep until they can gain their lost chi back.
Black Mask Worn by: Jade and Valmont (after being split into two halves) (this mask's halves were both worn willingly)
Summons: Crab Khan
Crab Khan have large sharp claws and stingers which, though big and heavy, do not slow them down.
Red Mask Worn by: Nobody
Summons: Mantis Kahn
Mantis Kahn have sharp deadly limbs and can move at great speeds.
Tarakudo's mask (forced on his face)
Once a mask has bonded to its host, it can only be removed using a magic spell with a specific key ingredient. The ingredients for each mask (named by tribe of Shadowkhan summoned) are as follows:
- Ninja - Japanese Steel
- Razor - Japanese Silk
- Bat - Japanese Rice
- Sumo - Rare Japanese Seaweed
- Samurai - Japanese Cherry Blossoms
- Squid - Tentacle of Japanese Octopus (also Tail of Lizard, Wolfbane, Sulfur Root, Left Eye of Newt)
- Shadow Eaters - Japanese Fish
- Crab - Japanese Monkey Tears
- Mantis - Japanese Leaves
- Tarakudo himself - Hair of Japanese Samurai