Takeshi is the primary antagonist of Yaiba. Originally a gifted high school swordsman, but when the fight he had with Yaiba ended in a draw, he made himself train harder. He eventually found a hidden basement containing the statues of Thunder God and the Devil Wind which was holding a sword. Upon wielding the Devil Wind sword, he was possessed and grew horns, turning into the Devil Wind incarnate. Although he uses the Devil Wind sword, he gave it to Yaiba upon acquiring the "Mao-Ken" Black Moon sword. Like all good villains, Onimaru has entire hordes of faceless minions who are nothing more than humanoid black bodies with eyes, mouths, and a single horn sticking straight up from the center of their head.

(Source: Wikipedia)