Owner of a small shop called Sabrina, Misukochi hires Nana Kotatsu for a while to work in its shop until he is forced to close down.
Mizukochi is the owner of a small shop named "Sabrina" that sells old fifties and sixties furniture. Nana Osaki and Komatsu came to his shop to buy some furniture for their new living place over at room 707. When Mizukochi mentions that he is having trouble maintaining the shop on its own Nana Komatsu asks him if she can work at his shop. Mizukochi hires Nana as a shop assistant until he is forced to close "Sabrina" down due to bad sales.
According to Nana Mizukochi is 29 years old.
Later on in the story Mizukochi send Nana Komtatsu a wedding card that tells that he is about to marry his child hood sweetheart.