He is a man with a slightly muscular figure and tan skin. He has red spiky hair and an indigo iris on his left eye. He has a black half-mask that conceals his right eye to contain his Evil Eye power from being used constantly.
Gaiza is a very serious and strict person whose only desire is to restore the power of the Fuuma clan to its former state before the Taimanin Civil War and gain vengeance against those that destroyed his and other allied families.
Gaiza is the young head of the Nisha family, one of the great families leading the Fuuma Clan. The Nisha are a relative great family of the protagonist's family, thus it would be correct to say that he and Kotarou are distant relatives. Gaiza's parents and siblings were all killed during the First Taimanin Civil War. Gaiza is now attempting to gain revenge against the Taimanin as well as restore the Fuuma Clan to its former glory and formed the Fuuma Shinobi Army.
Kaiju World War: Part 1 Edit
Gaiza, along with a battalion of Taimanin grunts, encounter Kotaro, Hebiko and Shikanosuke in the Gosha Academy, expressing disdain in the fact that Kotaro is the head of the family yet doesn't have an Evil Eye ability and never takes responsibilities he is supposed to uphold. Kotaro replies that he doesn't care about his "responsibilities" and wants to live on his own rules and wants, angering Gaiza further and prompting him to order his soldiers to kill him, along with Hebiko and Shikanosuke. However, Kotaro and the others escape, while Gaiza leads an insurgency to take over the school and Taimanin headquarters.
Kaiju World War: Part 2 Edit
Kotaro Fuuma Edit
Gaiza was childhood friends with Kotaro Fuuma. Before, he regularly played together with him and Hebiko. However, now he holds a deep disappointment for the protagonist who he considers to be a nobody and calls "Missing Eye."
Hebiko Aishu Edit
Along with Kotaro, Hebiko Aishu was his childhood friend, but unlike him, she still earns Gaiza's respect and admiration.
- Inoshishijo - It is Gaiza's signature long sword which has been passed down through the generations in the Nisha family.
- Kaiju Transformation - Gaiza also has the ability to transform into the black dragon kaiju Susano-no-Amakata.
Evil Eye: Yakusha Skull Edit
Gaiza's Evil Eye Yakusha Skull (扼者髑髏 Yakusha Dokuro , Skulls of Conquerors) calls upon restless souls of the dead and allows him to wear their lingering grudges and malice on his own body, thereby strengthening himself. When he activates it, his whole body is covered in a skull-like armor, and through his armored power and enhanced speed, he is able to obliterate his enemies. It can be used in either his human or kaiju form Susano-no-Amakata.