Manga Ubau Mono Ubawareru Mono

Seto Yu is a 12-year-old boy, that is abused violently by his father. One day, he is transported into a fantasy world with video game mechanics after being killed by his abusive father and he discovers that he has the unique ability to steal other people's skills for his own use. He quickly uses his special power to take revenge on the townspeople who bully him and obtains a harem of beautiful girls who love him unconditionally even though he shows no romantic interest in any of them and has the physical build of a skinny teenager