Mukuro has a cold, serious expression and a reserved personality. She is completely indifferent towards other people unless it's her sister Junko. Unlike her sister, she doesn't take any sadistic pleasure in hurting or killing people, but at the same time, she shows little concern for other people's suffering, regarding them more as tools such as when she was surprised Junko made all of the brainwashed Reserve Course students commit suicide despite how useful they could have been.