Eiko is a freshman student attending Babylus Demon School. She constantly tries to have a conversation with Iruma Suzuki ever since he saved her but fails every single effort throughout the series. She's somewhat sociable, as she's usually seen casually talking to multiple unnamed background characters, but mainly hanging with her close group of friends. She is shy when talking to people she admires, such as when she attempts to thank Iruma for saving her, on multiple occasions. In this way, she appears polite and kind in nature.