24 years old. The older twin. He has neat black hair, wears glasses, and is always dressed in a flawless three-piece suit. Calm, collected, and intellectual, but possesses a ruthlessness that stops at nothing to achieve his goals. He views the male student, Yo, as a treasure that must not be defiled, attempting to keep him under 24-hour surveillance. As they spend time together, his affection grows, and while treating Yo like a younger brother, he begins to enjoy playing dress-up with him. He doesn't particularly like his twin, Rin. They fight often.

24 years old. The younger twin. He has short hair with long bangs in the front and wears a messy white shirt with a jacket thrown over it. Intuitive and rough, but surprisingly straightforward and clingy toward those he likes. He loves teasing the male student, Yo, and is extremely sensitive about other people touching him. Before he knows it, he falls for Yo, teasing him like a child and becoming spoiled and needy around him. He doesn't particularly like his twin, Ai. They fight often.

72 years old. A small elderly man with neatly trimmed white hair and sharp eyes, clad in dignified traditional Japanese clothing. A feared figure in the underworld, but his judgment falters whenever his grandson is involved. He dotes on the male student, Yo, and is desperate to provide him with the highest quality education and absolute safety. He is occasionally exasperated by the twins, who lose their composure and act selfishly while bickering.