Helloween is a German heavy metal band founded in 1984 in Hamburg, West Germany by members of bands Iron Fist, Gentry and Second Hell. Its first lineup consisted of singer and guitarist Kai Hansen, bassist Markus Grosskopf, guitarist Michael Weikath, and drummer Ingo Schwichtenberg. By the time Hansen quit Helloween in 1989, the band had evolved into a five-piece, with Michael Kiske taking over as lead vocalist. Schwichtenberg and Kiske both parted ways in 1993, and there had been numerous line-up changes within the next two decades, leaving Grosskopf and Weikath as the only remaining original members. As a septet, their current lineup includes four-fifths of the Keeper of the Seven Keys: Parts I and II-era lineup, featuring three additional members, vocalist Andi Deris (who had replaced Kiske in 1994), guitarist Sascha Gerstner and drummer Daniel Löble.
Since its inception, Helloween has released sixteen studio albums, three live albums, three EPs, and twenty-nine singles, was honored with 14 gold and 6 platinum awards and has sold more than ten million records worldwide. Helloween has been referred to as the "fathers of power metal", and one of the so-called "big four" of the genre's early German scene, along with Grave Digger, Rage and Running Wild.