Kusumi Egawa, hailing from Hokkaido, carries the weight of a significant middle school incident involving her best friend, Ichi Tanaka. This event shattered the trust of those around her, leaving her fearful of speaking and often isolated. Despite this profound social withdrawal, she possesses exceptionally high combat abilities. Revered as one of the most skilled fighters since Yurigaoka Academy's founding, her prowess earned her the nickname "God's Child."

She finds support in Shiori Rokkaku and Soraha Amano; notably, Kusumi persuaded Soraha to continue as a Lily after her Legion disbanded. Beyond battle, Kusumi demonstrates culinary talent on par with a professional chef, particularly favoring the preparation of hamburgers and dumplings. She has a fondness for horses but exhibits a distinct sensitivity to loud noises.

Physically, Kusumi stands 154 cm tall and weighs 47 kg. Her birthday is March 27 and her blood type is AB.