Sullyoon

Sullyoon (설윤), born Seol Yoon A (설윤아) on January 26, 2004, in Daejeon, South Korea, is a lead vocalist and dancer of NMIXX, the six-member group under JYP Entertainment's SQU4D division. Her training background is longer than most of her groupmates'. She began taking ballet as a toddler, continuing into her teens while also developing the vocal skills that would eventually secure her a position in one of JYP's most competitive trainee pools. She studied at Hanlim Multi Arts High School with a major in Broadcasting and Entertainment — the same institution that Jiwoo also attended. Her path to JYP is notably unconventional. Before joining, she had already passed auditions at SM Entertainment, YG Entertainment, and several other agencies — a record that places her among a small group of idols who were wanted by multiple majors simultaneously. JYP ultimately recruited her through a private casting in 2020, after which she trained for approximately two years before NMIXX's debut on February 22, 2022, with the single album Ad Mare and lead track "O.O." Within the group, Sullyoon carries a dual designation that is both functional and public-facing: lead vocalist and visual. The visual designation in K-pop groups is the formal acknowledgment that a member's face will be used as a primary entry point for the group's image in promotional materials and brand contexts. Her vocal control, described by the group themselves as one of the cleanest in the lineup, adds a substantive dimension to that visibility. The two together make her one of the most consistently highlighted members in international fan discourse around NMIXX. She has a younger sister and a younger brother.