Billlie

Billlie is a seven-member girl group under MYSTIC Story, consisting of Moon Sua, Suhyeon, Haram, Tsuki, Sheon, Siyoon, and Haruna. They debuted in 2021 with "RING X RING."

The group became known for an unusually developed narrative concept built around mystery, memory, and the repeated question of what happened to "Billlie." Rather than using lore only as decoration, Billlie's albums, videos, and styling often connect back to that story world.

Musically, Billlie has moved through experimental pop, rock touches, jazzier textures, and bright dance tracks while keeping a theatrical edge. Tsuki's viral performance moment helped bring broader attention to the group, but the team's appeal is broader than one fancam: the members are presented as characters inside a larger pop project.

The fandom is known as Belllie've. Billlie's appeal comes from the balance between concept, lineup, and musical personality, with the lore adding texture without overwhelming the group's pop identity.