Koume Sakiyama works as a nurse at Jokei University Hospital alongside physician Inuki Akaya. She has long black hair, purple eyes, and consistently wears a medical eyepatch covering her left eye. Professionally, she displays notably poor bedside manners and maintains a harsh attitude toward patients.

She exhibits significant physical strength, demonstrated by carrying much taller individuals over her shoulder without visible strain. In combat, she employs a blood armament that manifests as a whip ending in a sharply pointed tip resembling a devil's tail. Activating this power causes her eyepatch to change color, turning red.

Despite her outwardly abrasive personality, Koume demonstrates genuine concern and loyalty toward Inuki Akaya, revealing a layer of care beneath her stern exterior. Her typical attire includes distinctive thigh-high socks extending to her upper thighs. Information regarding her background, personal history, or character development beyond her primary series role and interactions remains unavailable.