Fujiwara Kotori

A girl Shinji meets by chance. He thinks she's going off to kill herself but she was just sad and wanting to be alone. Shinji gives her a love letter by mistake but convinces her it was written for her. With abusive parents and no friends she clings to Shinji in desperation for friendship. When he tells her he's dying soon and wants to make many girls pregnant before he dies she reluctantly allows it.

Her 'favorite number' is 15