Julie-Su was a Mobian Echidna and the girlfriend and distant relative of Knuckles the Echidna. Born the daughter of Luger and Mari-Su, Julie-Su was brought up amongst the Dark Legion. After her parents were murdered by her half-sister Lien-Da she was placed in the foster care of Simon and Floren-Ca before she was taken away from them as well. Serving as a support troop in the Dark Legion for years, she eventually left it to join Knuckles and his group, the Chaotix. She served as a devoted member