Moon Sua x Billlie (Oldest Member)

Who is Moon Sua (Billlie)?

Moon Sua is a South Korean rapper, singer, MC, and lyricist under MYSTIC STORY who serves as the main rapper and lead vocalist of the girl group Billlie. Born Moon Su-a on September 9, 1999, in Cheongju, Chungcheongbuk-do, South Korea, she stands at 162.9 cm tall with blood type B. Her representative color within Billlie is purple, and she holds positions as both main rapper and lead vocalist.

In addition to her role in Billlie, Moon Sua forms one half of the group's official sub-unit Moon Sua X Siyoon. Her professional career spans multiple entertainment fields beyond group activities, including work as an MC and lyricist. Prior to joining MYSTIC STORY in 2019, she trained under YG Entertainment for nearly ten years, from 2010 to 2019.

Moon Sua gained recognition in the Korean hip-hop scene as a contestant on the competition show Unpretty Rapstar 2 in 2015, where she advanced to the final round and finished as third runner-up. The rapper officially debuted with Billlie on November 10, 2021, through the release of their first mini album The Billage of Perception: Chapter One. Her multifaceted skill set encompasses rapping, singing, MCing, and lyric writing, establishing her as a versatile performer within the K-pop industry. Moon Sua's artistic identity blends her hip-hop foundation from her trainee years with the vocal and performance requirements of her current position in Billlie.

Moon Sua's Career Journey

YG Entertainment trainee years

Moon Sua began training under YG Entertainment in 2009 at age 13. She was revealed as part of Future 2NE1, a predebut group that included Im Suah (soloist Youha), Park Seoyoung (Produce 48), and Lee Seoyeon (Fromis_9). The Future 2NE1 members appeared as child dancers in G-Dragon and T.O.P's "Knockout" music video. During her trainee period, YG Entertainment granted Moon Sua permission to appear in external projects, which was uncommon for the agency's trainees. In 2016, YG Entertainment announced plans for a new girl group that would become BLACKPINK, with Moon Sua considered a likely candidate for the lineup, though she was never officially included. A YG representative clarified in May 2016 that "Moon Sua is a trainee that still has a long way to go" and was not among the new girl group members. She departed YG Entertainment in April 2019 after nearly ten years.

Unpretty Rapstar 2 appearance

In 2015, Moon Sua participated in Mnet's competition show Unpretty Rapstar 2, competing against eleven other female rappers including Yezi (ex-Fiestar), Hyorin (ex-Sistar), Heize, Yubin (ex-Wonder Girls), and Exy (WJSN). She advanced to the final round and placed as third runner-up. For the semi-final round, Moon Sua performed her self-written song "Who Am I" with AKMU's Suhyun. YG Entertainment issued a clarification stating the agency was not "in a circumstance to support or give her strength" during the competition, emphasizing that Moon Sua was "fully aware of this" and "giving her all to the program".

Debut with Billlie

Following her departure from YG Entertainment, Moon Sua was officially revealed as a trainee under MYSTIC Rookies on February 19, 2020. During her time as a Mystic Story trainee, she participated in several Listen Stages in 2019 and 2020, which were casual YouTube live streams featuring vocal covers lasting over 30 minutes. Moon Sua was subsequently announced as a member of MYSTIC STORY's upcoming girl group Billlie. The group released their first mini album The Billage of Perception: Chapter One on November 10, 2021.

Moon Sua X Siyoon sub-unit

On April 1, 2025, Mystic Story announced that Moon Sua and Siyoon would debut as Billlie's first official sub-unit. The duo released their digital single "SNAP" featuring sokodomo on April 7, 2025, at 6 p.m. KST. The track combines drill's low bass and minimal rhythms with electronic pop synth sounds, reinterpreted in the hyper hip-hop genre. Both Moon Sua and Siyoon participated in writing the lyrics, with sokodomo contributing to composition and lyrics. The music video surpassed 1 million views on YouTube within six hours of release. An English version of "SNAP" was included with the single release.

Moon Sua's songs and discography

Moon Sua's discography encompasses 68 songs, spanning group releases with Billlie, solo endeavors, and collaborative projects. Her solo work includes "Like a Star," released on December 10, 2022, as part of the Reborn Rich OST Part 4, which featured in the South Korean drama series. The track, composed by Oh Sung-hoon and OneTop (Sung Kyu-ho), with lyrics by Oh Sung-hoon and Hyegaseo, demonstrated her capabilities beyond group activities.

In addition to group work, Moon Sua participated as a featured artist on multiple releases. She collaborated with ASTRO on "Moon" in 2025 and appeared on ANODE's "Keep It Raw" along with its English version, both released in 2025. Coupled with her sub-unit activities, she featured on ARrC's "WOW (Way of Winning)" with Siyoon in 2025.

Her writing credits extend across Billlie's discography, with contributions adapted from KOMCA including rap-making for "Patbingsu". Notable Billlie tracks featuring her work include "GingaMingaYo (the strange world)," "EUNOIA," "RING X RING," and "flipp!ng a coin". During her participation in JTBC's The Second World competition, she released "Night Dream" as part of Episode 8 in October 2022.

Moon Sua facts and personal life

Family and background

Moon Sua was born in Cheongju, South Korea. She attended Seowon Middle School and graduated from Hanlim Arts High School. Her family consisted of her parents and older brother Moonbin of ASTRO, who was one year, seven months, and fourteen days older than her. Both siblings shared blood type B and IxFP personality types. Their mother worked as a model and actress. As a child, Moon Sua played the violin and was active as an ulzzang alongside her brother before their idol careers.

Hobbies and interests

Her hobbies include photography, nail art, and watching Netflix. She crafts accessories for herself and friends. Moon Sua's favorite color is purple, and she cites CL as her role model. She describes herself as a homebody who stays under the blanket on holidays and identifies autumn as her favorite season. Her life motto is "there's a time for everything".

Friendships and connections

Moon Sua maintains close friendships with multiple female celebrities, including Heize, Truedy, FIESTAR's Yezi, GFRIEND's SinB, KARD's Jiwoo, BLACKPINK's Jisoo, 4Minute's Jiyoon, Hello Venus's Yeoreum, Akdong Musician's Suhyun, actress Kim Sae-ron, and NMIXX's Haewon. Her connections stem from her YG Entertainment training period and industry relationships developed throughout her career.

Health hiatus and return

Moon Sua entered hiatus in April 2023 following her brother Moonbin's passing. She resumed activities in June 2023 but announced a second hiatus in September 2023 due to health concerns. During her break, she traveled, spent time with friends, exercised, and maintained connection with fans through Weverse. She officially returned to group activities on April 12, 2024, alongside fellow member Suhyeon.

FAQs

Commonly referenced information about Moon Sua addresses her specific role, personality characteristics, and personal preferences. Within Billlie, she functions as the main rapper and lead dancer, with her powerful stage presence and charismatic performances defining her contributions to the group. Her career trajectory involved over 10 years as a trainee before gaining attention on Unpretty Rapstar 2, where she finished as a finalist, highlighting her rap skills and resilience prior to her eventual debut with Billlie.

Personality-wise, Moon Sua exhibits traits of resilience, charisma, empathy, dedication, and playfulness, maintaining a confident and hardworking demeanor with a cool rapper edge. She expresses warmth in discussions about music and life, with her empathy particularly evident when connecting with fans. Her preferences include writing lyrics, performing on stage, spending time with Billlie members, and fashion, while she dislikes giving up, stagnation, and seeing loved ones upset.

Additional characteristics include her reputation as the member most likely to keep a secret according to Suhyeon and Sheon. She identifies her Indian dimples as a distinctive charm. In 2023, she took on responsibilities as an MC for MBC's Show Champion alongside Tsuki and woo!ah!'s Nana.