Helloween, Kai Hansen was born in 1963 in Hamburg, West Germany. He began his musical career in 1978 alongside Iron Saviour co-founder and producer Piet Sielck in a group called Gentry. He formed Helloween in 1983 with guitarist Michael Weikath, and stayed with the band until 1989, appearing on an EP and three full-length albums, including the group's landmark Keeper of the Seven Keys, Pts. 1-2. After leaving Helloween, Hansen formed his own power metal group, Gamma Ray, which became one of the most prominent and prolific acts in the German metal scene. He has appeared with and performed on albums with a myriad of like-minded artists, including Blind Guardian, Angra, ex-Helloween vocalist Michael Kiske, Hammerfall, Storm Warrior, and Unisonic. In 2016 he released his first solo album, XXX: Three Decades in Metal, followed by the concert LP/DVD Thank You Wacken in 2017.