Switch's Girlfriend - Yuuki Reiko (OH MY SATAN!)
Yuuki/Yuki and her "OH MY SATAN!"
Reiko Yūki (結城 澪呼, Yūki Reiko) is a member of the Occult Research Club who is knowledgeable about spiritual, suspicious subjects. She is Switch's sworn rival and the two have had several disputes over the existence of ghosts.