Ren's first appearance when she saw Kazuki wounded and thought he's a girl. She's giving Kazuki a medicine and tell him to drink it. However, Kazuki lose his consciousness so Ren decided to drink it for him by kissing him. Later on, Kazuki found himself in a small clinic as Ren found out he's a guy. As she and her grandfather Gen decided to help him to locate MakubeX.