Hizuru Minakata is an author who writes using the pseudonym Ryuunosuke Nagumo.
She has a double personality, the second of which is her dead twin brother, Ryuunosuke Nagumo.
In actuality, it is Ryuunosuke's shadow that is within Hizuru. He takes control whenever they must fight, so as not to make Hizuru's hands dirty. They eventually manage to properly meet and talk to each other within their mind, which they were unable to do prior. Afterwards, they take control in tandem, where Ryuunosuke is in control of her body to fight, while Hizuru talks to Haine at the same time
