![ONF 2021 LIVE CONTACT :: CODE #1. [REVERSE]](https://image.tmdb.org/t/p/original/4wjPi5x2igYJI9jrbE5QcJhSW8X.jpg)
[Reverse] is the first concert held by ONF. It was held across four days from December 9-12, 2021, at Yes24 Live Hall in Seoul, South Korea.
Park Min Kyun, better known by his stage name MK, is the vocalist, rapper, dancer and composer of the boy group ONF. He was a Starship Entertainment trainee and a prospective member of MONSTA X. He participated in MIXNINE and came in 22nd place, hence eliminated.