Kotowari: Kimi no Kokoro no Koboreta Kakera

As a child, Mishira Tsuina was saved by an unknown woman from a mysterious mystical creature from the afterlife. During the rescue, the boy received wounds on his hands and lost a piece of his soul. Along with this, a part of his soul was gone, and his memory. A mysterious girl named Kazamidori took over his upbringing, but soon she was gone: she died in a battle with another mystical creature called Kotovari. After entering high school, he met a classmate, Yuigahame Yuki, who bore a striking resemblance to Kazamidori. This landmark meeting was fatal for him and changed his life forever.