Marron is a slender woman with long brown hair. She wears a standard Marine uniform of a white button-up shirt, a Marine cap, blue pants, a white kerchief around her neck, and a white coat over her shoulders.
Marron accompanied Sentomaru and Hina to raid the Pirates Festival on Delta Island. She traveled inward to confront the pirates, but while she was clashing with one, Bullet used his abilities to assimilate with the island. She and the pirate she was fighting noticed a wave of Bullet's purple substance and stopped fighting to retreat.