Fumiko always tends to act childish and perverted on purpose and appears to have a playful attitude most of the time. It's rare to see her get embarassed or upset. She joined the Devil Hunter organization after her parents have been killed by a Gun Devil, and used to blame Chainsaw Man for that. But this event only increased her sympathy in him, when she saw that he had feelings too. Since then, she's a fan of Denji and has to keep an eye on him, due to Yoshida's order.