Battle Royal High School

Riki Hyoudo, a student at Battle Royal High School, wears a tiger mask while practicing kung fu, which is unremarkable given the school's martial arts culture. Unbeknownst to Riki, he shares a parallel existence with Byoudo, Master of the Dark Realm, whose world is connected to their own through a dimensional gate. This gate's opening allows the evil Fairy Master to manipulate Byoudo, prompting him to invade their world, and as a result, Riki becomes semi-possessed by his counterpart.