When first seen, Umanosuke is cool and composed, and almost suave. He even has no problem with letting Fuu escape as long as he can kill Mugen. Upon his meeting Mugen, the composure crumbles, worse when the eye patch is cut away, and he spirals to Denkibou's level of madness. At this point, Umanosuke sports possibly the greatest destructive intent in the entire series, attacking in a berserk flurry of vicious attacks. Mugen gives up his sword in order to rescue Fuu from his clutches, but manages to reclaim it and, after a hard-fought battle, decapitates Umanosuke with his own weapon. The way he ends the battle is important; in the earlier battle against Kariya, Mugen is told that simply fighting on instinct shows everyone his limits and is soundly defeated. The manner in which Mugen works out Umanosuke's death shows Mugen overcoming his weakness.