Akuheki
Ongoing | Iimo | 2017 released
Note to myself: This story is so good. The guy who became a masochistic because of what happened with his childhold, and the other guy who became a "monster" because of what happened in his childhood too. He takes care of his grandmother and "killed" her, and the light-haired guy wants to be killed, and so he triggered the monster in him. There are more to the story than this.
Dead or alive