Misuzu Ōyama

Misuzu Ōyama (大山 美鈴, Ōyama Misuzu) is the owner of the apartment building that Hei stays at in Tokyo. Misuzu has grey hair tied up at the back of her head where it is held with a pin which has a red ball at one end and dark-colored eyes. Misuzu frequently chases Mao away from the building. She also likes to compliment Hei for being such a good boy.