Kasumi is a cheerful, elegant and friendly person with a seemingly perfect life, as she received a Shujin scholarship. She also appears to be quite clumsy and careless, as she is shown outright missing the mark at the batting cages even if her reflexes are usually excellent, and she lets her phone's battery run out while texting the protagonist. Despite the fact that she can cook, she is unpredictable and somewhat clumsy at it, since she isn't sure about the ingredients, and she often uses stamina replenishing food due to her gymnast tendencies. It's because of that she eats a lot, that she considers a "normal" amount for a gymnast like herself and she also has large lunch box to prove this.