Animation XXX - Keraku-no-oh: King of Pleasure 3

Ryouichi has no friends, is often beaten by bullies, and even his own parents have given up on the young man. When a new lady joins his class, his life takes a dramatic turn for the better. Ryouichi was a childhood buddy of Chihiro's, and she recalls him well. It's not clear to her that he was injured when they were playing as youngsters and has had brain damage ever since. She agrees to do everything for him out of a deep sense of shame. In order to take advantage of this, Ryouichi demands sex from her. It's impossible for Chihiro to back out, so she accepts. As time goes on, Ryouichi discovers that he's invincible in the bedroom and possesses a hidden weapon. After enduring years of bullying at the hands of his peers, he has only one goal in life: revenge. A perverted trip to transform all the ladies who rejected him into his own sex slaves is what he intends to do.