She is the leader and main vocalist of HUNTR/X, a K-pop girl group that also operates as a trio of demon huntersRumi is the daughter of the late Mi-yeong Ryu, a former demon hunter, and a demon father. She was raised by Celine, a member of the Sunlight Sisters, who taught her during childhood to hide her demonic heritage and that by fulfilling her purpose of sealing the Golden Honmoon, her patterns would disappear. Throughout the film, Rumi struggles with her dual heritage, concealing her markings and fearing rejection from both her team members and her fanbase