Sion (시온), born Oh Si-on (오시온) on May 11, 2002, is a South Korean singer and dancer from Mokpo, South Jeolla Province, South Korea. He is the leader and eldest member of NCT WISH, a six-member boy group under SM Entertainment and the final sub-unit of NCT. Sion was discovered by SM Entertainment through social media and subsequently joined the company as a trainee, undergoing approximately four years of training. In June 2023, he was introduced as a member of SMROOKIES alongside fellow NCT WISH member Yushi. Later that year, he appeared on the pre-debut reality competition NCT Universe: LASTART as one of two members already confirmed for the group's debut lineup. Following pre-debut activities under the name NCT NEW TEAM, he officially debuted with NCT WISH on February 21, 2024, during SMTOWN LIVE 2024 SMCU PALACE @TOKYO at Tokyo Dome. Known for his smooth vocals, refined dance technique, and composed stage presence, Sion plays a central role in NCT WISH's performances and group activities. As the group's leader, he is recognized for his calm demeanor and supportive approach to his fellow members. Through music releases, concert tours, and international performances, he continues to develop his artistry while guiding NCT WISH's growth as a group.