En Butter was a six-member boy group formed for Boys Planet's Artist Battle. The group was made up of K-Group's Pentagon's Lee Hoe-taek (후이), ex-1THE9's Lee Seung-hwan (이승환), ZEROBASEONE's Kim Gyu Vin (김규빈) and Park Gun Wook (박건욱), TIOT's Kum Junhyeon (금준현), and G-Group's Hiroto (井汲大翔), Together, they performed and released "En Garde".