Imai Nobume is a vice captain and part of the assassination unit of Mimawarigumi.

She is emotionless in her facial expression and speech. She is sadistic and likes to cut people down. According to Isaburo when she switches into her assassin mode, she doesn't stop until she kills everyone in the vicinity. Her favorite food are donuts. She can becomes so obsessive about them, to the point where she uses violence to get them.

Nobume alongside Kagura and Princess Soyo are known as the "Sisterhood Sadist Three".