Chizuru Maru (丸流千鶴 Maru Chizuru) is one of the supporting characters of Boarding School Juliet series and a member of Black Doggie House.
- His name is based on the dog breed, "Maltese".
- He has a crush on Juliet's guise as Julio, having realized she is a girl but not of her true identity in the beginning. After learning that Julio is a girl, he tries to be friend with her.
- It is said, he is one of the strongest of his generation in the Black Doggies after Romio who is shown to be stronger than him.
- It is suggested he secretly respects Romio's strength but he pridefully denies it.
- Despite his brutal manner, he cares for his friends in spite of insulting them.