Helloween formed out of the remains of the two smaller local acts Iron Fist and Second Hell culminating in the membership of Michael Weikath (vocals/guitar), Kai Hansen (guitar), Markus Grobkoff (bass) and Ingo Schwichtenberg (bass). After hacking around for a few years they were signed by local label Noise International' to release an eponymous EP in 1985. By the time the album proper Walls Of Jericho was issued later the same year press interest was growing. Often considered (and not incorrectly) as part of NWOBHM movement, by 1986Helloween's Power-Metal approach was in full swing with the addition of a dedicated vocalist in the form of teenager Michael Kiske whose mix of Bruce Dickinson/Rob Halford vocals kept the follow-up album Keeper Of The Seven Keys - Part I (1987) powerful and yet melodic at the same time and proving popular with the grassroots Metal fandom in polls taken that year. The album saw a clear shift to them adopting a more fantasy lyrical content and the highly popular NWOBHM musical style. The band was now selling out wherever they went in Europe and the follow-up Keeper Of The Seven Keys - Part II (1988) reflected theirnewfound fame by making it to 24 in the U.K.
After the 26 U.K. charting live set Live In The U.K. with newcomer Jorn Ellerbrook on keyboards, Hansen buggered off to form Gamma Ray with Roland Grapow replacing him on guitar. In 1991 the long awaited studio set Pink Bubbles Go Ape, despite making 41 U.K. on major label EMI' was considered a disappointment by fans and critics alike, ditto for the 1993 follow-up Chameleon.The problems for the band were just beginning for during the Chameleon tour, the band would routinely play to half-filled venues, the fans staying away when faced with the prospect of having to sit through a set of nearly all songs off the new album. Worse yet, drummer Ingo Schwichtenberg fell ill due to mental and drug-related issues, and was eventually fired, replaced by session drummer Ritchie Abdel-Nabi. Meanwhile, the conflicts within the rest of the band had reached critical mass, with Michael Weikath refusing to work any longer with Michael Kiske. The decision was made to also fire Kiske. In hindsight, the recent move away from Power Metal to Pop was Kiske's idea; he had taken on a more vocal role in the band, and did not hide the fact that he disliked Helloween's style of Power Metal, instead favoring a softer, Pop style of music. Since his firing, Kiske has not spoken positively about his time with the band, and still claims to hate the whole Heavy Metal scene. Kiske would return with a solo album, 1996's Instant Clarity. The album was, for the most part, Pop and soft rock, except for The Calling, co-written by Kiske and Iron Maiden guitarist Adrian Smith, and the Smith, Kai Hansen and Kiske-penned New Horizons as the only "heavy metal" songs on the album. Since his first solo effort, Kiske has performed eclectic sounding albums, occasionally he has been known to guest on other albums by other bands, but refuses to be credited by his given name in an effort to prevent being associated with the metal genre.
In addition to the firing of Kiske, Abdel-Nabi, whose inability to replicate Schwichtenberg's machine-gun style of drumming hindered Helloween's ability to play fan-favorites like Eagle Fly Free and How Many Tears live, was given his walking papers as well. 1993 would come to a disastrous close as, in short, the band had no singer, no drummer, and no record contract ('EMI' let the band go after the horrible returns for Pink Bubbles Go Ape and Chameleon).
In 1994 Andi Deris (ex-Pink Cream 69; vocals) replaced Kiske, and Uli Kusch (ex-Gamma Ray) replaced Schwichtenberg on drums. Now on Castle/Raw Power' the albums released in the aftermath were mediocre fantasy driven albums that would make the template for the rest of their career including Master Of The Rings (1994), The Time Of The Oath (1996) and the live set High Live (1996). Better Than Raw (1998) was probably their most realized performance since Hansen's departure while Metal Jukebox was just that, a collection of 70's covers many of which the Heavy Metal fans would not relate to, including one of Abba's Lay All Your Love On Me.
The story of Helloween's return was tempered, however, by tragedy in 1995, as the band, its members and fans were saddened by the suicide of original drummer Ingo Schwichtenberg. In the years since his departure from Helloween, Schwichtenberg had spiraled deeper into drug-use and depression; additionally, he was never able to recover emotionally after being fired from the only band he had ever known. The former drummer committed suicide by jumping in front of a train. Dedicated to his memory was 1996's The Time Of The Oath that served to helpre-establish the band as a popular European Metal band.
In 2000 they changed to Nuclear Blast' to release The Dark Ride but it was here that membership changes would again happen when Helloween parted ways with guitarist Roland Grapow and drummer Uli Kusch. Grapow and Kusch had pushed to continue the direction that the band had taken with The Dark Ride; Weikath, meanwhile, weary of other band members trying to change Helloween's musical direction and not wanting a repeat of the Kiske situation, collaborated with Deris and Grosskopf to fire Grapow and Kusch via e-mail. The two now ex-members went on to form Masterplan, while replacements for them were soon found in guitarist Sascha Gerstner (ex-Freedom Call, Neumond), and drummer Mark Cross (ex-Metalium, Kingdom Come; currently in Firewind) with whom began the recording of another studio album, entitled Rabbit Don't Come Easy, in 2003. Cross could not finish the album due to mononucleosis, completing only two tracks; the drum tracks were completed by Motörhead's Mikkey Dee. Stefan Schwarzmann, former drummer of Running Wild and Accept would shortly thereafter take over the drumming duties. Despite a somewhat tepid response to the album, Helloween nonetheless completed a successful world tour and follow-up massive 3 CD best of compilation Treasure Chest. Additionally, the band toured the United States for the first time since 1989 playing to sold-out crowds at nearly every venue.
2005 saw yet another line-up change following the tour as it became apparent that Helloween and Stefan Schwarzmann did not share the same musical vision. As further noted by the band, he had some trouble performing fast drum parts, so he was replaced by Dani Löble, the previous drummer of German metal band Rawhead Rexx. A change in record company also followed as they inked a deal with German label 'SPV'. Any fears that what had now become a revolving door of band members would affect the quality of their new album were laid to rest as Helloween's new studio album, entitled Keeper of the Seven Keys - The Legacy, was released in October 28th, 2005 in Germany, and November 8th in the U.S.A. to commercial and critical acclaim. The album had a pre-release single, Mrs. God, as well as a video for the track. The track Light the Universe was released as a single on November 22nd, featuring Candice Night of Blackmore's Night on guest vocals. She also appears in the video clip for that track.
In late 2006, Helloween filmed and recorded shows in São Paulo (Brazil), Sofia (Bulgaria) and Tokyo (Japan), for their live album Keeper Of The Seven Keys - The Legacy World Tour 2005/2006. The DVD also featured extra footage of the band as well as interviews and a road movie. This is the second Helloween live album to feature Andi Deris as frontman, and third overall.
Helloween has since completed their latest studio album Gambling With The Devil, which was released on October 23, 2007. It is noted for featuring more keyboards. As Long As I Fall was the first single, released in early September available only via download.
Helloween then teamed up with Kai Hansen's current band Gamma Ray for the subsiquent world tour, entitled Hellish Rock 2007/2008, that started in early November of 2007. Helloween headlined and Gamma Ray were labeled as the "very special guest" with most shows going along fellow German "guest" Axxis. The tour was notable for Kai Hansen stepping on stage with his former bandfellows Weikath and Grosskopf to perform I Want Out and Future World in the last encore segment of Helloween set.