Rei Shimizu is a playable third-party/book character in Super Smash Bros. Phi & originated from Danganronpa Gaiden: Killer Killer as the main antagonist of Chapter 2 in her respective manga. She was introduced as a suspect in the murder of Hana Niyama who was killed in the Ongō Hospital. While investigating the crime scene Misaki noticed the murder weapon was a scalpel in the victim leading to them suspect that the murderer is a doctor. Rei was then interviewed by Misaki and Takumi Hijirihara in the hospital staff, but Takumi couldn't even say anything before falling in love with Rei by first sight causing him to faint.