After she was rejected by her first love, Sunako developed an obsession with darkness and a morbid fascination with blood, horror movies, and similarly dark things. She hates excessive light exposure and also does poorly in hot weather, though the latter is because she grew up in northern Japan. She has three "friends"; a skeleton called Josephine and two anatomical figures named Hiroshi-kun and Akira-kun. While she suffers from severely low self-esteem, she is actually beautiful and a frighteningly tough fighter, being able to lift someone twice her size with one hand. She is portrayed throughout the manga in Super deformed form or chibi.