Satou's Aunt is always depicted as very cheerful, always with her unnatural smile, piercing stare and erratic behavior. There have been no scenes where she isn't smiling. She is shown to be a masochist as she would often invite men into her room, sometimes murderers in order to feel loved. Other times she would even sexually assault men. However, her victims can't hit her as she stares at them with her bloodshot eyes, Thus making them slightly paranoid. Despite this promiscuous behavior often getting her stitches, she doesn't stop, even trying to seduce Detective Iyada, the police interrogated her. She is also shown to be someone who is very calm, showing no reaction when Satou shared that she killed someone, rather much so congratulating her for doing that for someone she loves. Towards strangers, she can be quite welcoming and playful to them, but she can be rather off-putting when inviting people to come in due to her masochistic tendencies. She doesn't understand what most call love, so she tries to protect other peoples "love" hence why she does things that make her seem unstable, her perceptive of love is viewed as toxic, letting anyone do anything they want to her. She tries to protect Satou's love for Shio. There is little documented about her past or why she acts in ways such as this.