Xi Slayer Number 4 is one of the participants in the Demon King Slayer Project, appearing as a large lizardman in human-animal hybrid form. He wields a super laser gun and was engaged in a fierce battle with a smaller lizardman (another Xi Slayer). Number 4 is described as moving extremely nimbly, dodging laser beams and light balls. During the fight, he was deeply shaken when the smaller lizardman cried Star Lord and loosened his grip, but was then stabbed through the chest and abdomen with a short knife. In a furious response, he enlarged one of his hands and slapped the smaller lizardman, sending it flying dozens of meters. He was severely injured and reverted to a human form resembling an ancestor before kneeling down.
