Bikuni

was the leader of a group of yōkai in control of the eastern mountains. They went up against an army of kappa led by Jaken, and Bikuni went up against Jaken himself. He would have eaten Jaken, or used his teeth to tear him apart, if Sesshōmaru had not appeared at that moment. Sesshōmaru demanded they get out of the way, and when Bikuni did not move, he used his poison whip to slay Bikuni and his remaining yōkai. This encounter is what led Jaken to following Sesshōmaru.