My Girlfriend is a Serial Killer (2019)

Other name: 羊とオオカミの恋と殺人 hitsuji to okami no koi to satsujin love and murder of sheep and wolf 我的女友是殺人鬼

Synopsis:

Etsuro Kurosu faills getting into a university and becomes a hikikomori. One day, he tries to hang himself from a hook on the wall in his apartment. He fails, but his attempt leaves a hole in the wall. Through the hole wall, Etsuro Kurosu can now see Rio Miyaichi. He becomes fascinated with the girl that lives next door. Later, while peeping at her through the wall, Etsuro Kurosu sees her in the process of brutally murdering someone. He screams and is caught by her. Etsuro Kurosu confesses that he loves her and they start to date. Etsuro Kurosu feels happiness in his life, but what will happen to him? Will he be murdered by Rio Miyaichi?

Also known as: 羊とオオカミの恋と殺人 hitsuji to okami no koi to satsujin love and murder of sheep and wolf 我的女友是殺人鬼