2. Makoto Itou (School Days)
Its story is quite interesting. Makoto Itou falls in love with a girl, but after dating her a while he realizes that he is not getting sexual satisfaction, so he became sexual to his one friend Sekai and he makes her pregnant.
With all that Makoto Itou makes her life hell, and of course she (Sekai) kills him in the end. And when she kills Makoto Itou, his girlfriend kills Sekai to get revenge of her boyfriend’s death.