Mizuka Irei is Misaki's friend.
Mizuka has been a friend of Misaki's during their high school years. When Mizuka was hit by a car and paralyzed from the waist down, Misaki was the one to give her robotic legs that allow Mizuka to move about without the use of a crutch or a wheelchair.
Mizuka Irei is created by 5pb, and she has no information regarding any inspiration used to create her. She first appears in Robotic;Notes visual novel game and makes her first anime debut in episode 1. Mizuka is voiced by Takako Honda.