Mirea Mizushima is the younger sister of the commander of the evil organisation "Jackal", Crea Mizushima. She lives with her sister and make meals for the members of Jackal. Mirea is the classmate of Katsuragi. She seems to have strong feelings towards him. Mirea is the person who recommended Katsuragi to her sister as a good candidate for Ratman project.
She lived for a part of her life in rural England. Her parent passed away in what her sister told her was an accident.