German power metal band Helloween was established in 1984 by former members of Iron Fist, Gentry, Second Hell, and Powerfool. The group’s inaugural line-up included drummer Ingo Schwichtenberg, bassist Markus Grosskopf, guitarist Michael Weikath, and singer and guitarist Kai Hansen. The group is credited as being one of the most influential European heavy metal bands of the 1980s. The group had become a five-piece by the time Hansen left Helloween in 1989 to start Gamma Ray, with Michael Kiske taking over as the lead vocalist. There have been numerous lineup changes between then and 2016, leaving just Grosskopf and Weikath from the initial lineup. As a septet, they currently consist of four of the original members from the Keeper of the Seven Keys: Parts I and II (1987–1988) era, plus vocalist Andi Deris (who took Kiske’s place in 1994), guitarist Sascha Gerstner, and drummer Daniel Löble.
Helloween has released 16 studio albums, 3 live albums, 3 EPs, and 30 singles since its beginning. They have also received 14 gold and 6 platinum awards and have sold more than 10 million records worldwide. The “fathers of power metal” and one of the “big four” of the early German power metal movement, together with Grave Digger, Rage, and Running Wild, as well as one of the “big four” of power metal generally, along with Blind Guardian, Sabaton, and DragonForce, are Helloween.