Mars: Tada, Kimi wo Aishiteru

Kira is a sweet young girl with a traumatic past. She meets Rei who made her overcome her inner struggles. However, as much as they wanted to live as close to perfect as a couple can be, Kirishima tries to shake their relationship. Kirishima is a disturbed being who was bullied when he was young, and his outlook on life is what makes him do dark things.