Helloween formed in 1984 in Hamburg, Germany. The original line-up included Kai Hansen on vocals and guitar, Michael Weikath on guitar, Markus Grosskopf on bass, and Ingo Schwichtenberg on drums. That year, the band signed with Noise Records and recorded two songs for a Noise compilation record called Death Metal. The compilation featured the bands Hellhammer, Running Wild, and Dark Avenger. The two tracks were "Oernst of Life" by Weikath and Hansen's "Metal Invaders," a faster version of which would appear on the band's first full-length album.
Helloween recorded and released its first record in 1985, a self-titled EP containing 5 tracks. Also that year, the band released its first full-length album, Walls of Jericho. During the following concert tour, Hansen had difficulties singing and playing the guitar at the same time. Kai's last recording as the band's lead singer was in 1986 on an EP titled Judas, which contained the song "Judas" and some live tracks. Following these releases, Helloween began the search for a new vocalist.