Roots of NU'EST

After School (Korean: 애프터스쿨) was a South Korean girl group formed by Pledis Entertainment, with an admissions and graduation concept. After School officially debuted in January 2009 with the song "Ah!" from the single album New Schoolgirl. Following the addition of Uee in April of that year, they released "Diva", which won the "Rookie of the Month" award at the Cyworld Digital Music Awards.

BtoB is a South Korean boy band formed in 2012 by Cube Entertainment. The group consists of Seo Eun-kwang, Lee Min-hyuk, Lee Chang-sub, Im Hyun-sik, Peniel and Yook Sung-jae. Originally a septet, Jung Il-hoon departed from the group on December 31, 2020.

VIXX is a South Korean boy band formed by Jellyfish Entertainment through the 2012 reality show MyDOL. Originally a sextet, the group is currently composed of four members: N, Leo, Ken and Hyuk—former vocalist Hongbin and rapper Ravi left the group in August 2020 and April 2023, respectively. They are predominantly known as a "concept or performance group" whose music, lyrics, choreography, and overall stage performances are crafted together to tell a story or concept.