By the time Hansen left Helloween in 1989 to form Gamma Ray, the band had evolved into a five-piece, with Michael Kiske taking over as lead vocalist.

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.

We heard Queensryche, the first album that they did, and we thought wow that would be cool to have a singer like that who could be very stable on the high soaring notes and have a lot of expression.

[10] With their new lead vocalist in tow, Helloween approached record labels Noise International and RCA and proposed the release of a double-LP to introduce the line-up.

The album was released by Noise Records on 23 May 1987, months after the band spent the winter of 1986 into 1987 hard at work inside Horus Sound Studio in Hannover, Germany.

Due to guitarist Michael Weikath's illness, he was recovering from a nervous breakdown, all the rhythm guitars on the album were played by Hansen.

The band got the chance to perform, in front of 100.000 people, as a part of the Monsters of Rock festival along with Iron Maiden, David Lee Roth, Kiss, Megadeth and Guns N' Roses at Donington Park on 20 August 1988.

For "I Want Out", Hansen very publicly laid out his disillusion with life as a member of Helloween at this time,[13] explaining: "It was a statement, yeah.

Grapow, who was a car mechanic at the time, stated in 2017 that, if Weikath had not happened to ask him to join the band, he would have kept his job and given up on his dream of becoming a professional musician.

"[16] The inaugural Headbangers Ball Tour started in April 1989 with Helloween joining San Francisco Bay Area thrash metal band Exodus in support of headlining act Anthrax.

[18] They played their first show on their "Quick Hello Tour" in Hamburg 30 April 1992 and continued with some more dates in Europe and the band also went to Japan in the autumn of 1992.

After a long telephone call with Weikath, in which he explained why they had made that hard and painful decision, Schwichtenberg was asked to leave Helloween.

In 2008, Kiske released Past in Different Ways; an album featuring most of his old Helloween songs, albeit rearranged and re-recorded acoustically.

"1993 would come to a close for Helloween with no singer, no drummer, and no record contract (EMI released the band from its agreement for the low sales numbers for Pink Bubbles Go Ape and Chameleon).

"Helloween returned in 1994 with former Pink Cream 69 frontman Andi Deris as their new lead vocalist and Uli Kusch, formerly of Kai Hansen's Gamma Ray, on drums.

8 March 1995, original drummer Ingo Schwichtenberg committed suicide by jumping in front of a train in his native Hamburg.

"[23] Later in 2012, on an interview with Metal Shock Finland's Chief Editor, Mohsen Fayyazi, Grapow stated: I felt very secure in Helloween.

It was a great time in Helloween... but I am happy when I left the band after Dark Ride because it's one of my favourite albums, it changed my life totally.

Despite a somewhat tepid response to the album, Helloween nonetheless completed a successful world tour, highlighted by the return of classic songs such as "Starlight", "Murderer", and "Keeper of the Seven Keys" to the setlist.

2005 saw yet another line-up change, following the "Rabbits on the Run" tour, as it became apparent that Helloween and Stefan Schwarzmann did not share the same musical vision.

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.

[27] Helloween teamed up with Kai Hansen's current band Gamma Ray for their 2007–2008 "Hellish Rock" world tour, which started in early November 2007.

The tour is notable for Kai Hansen stepping on stage with his former band fellows Weikath and Grosskopf to perform hits "I Want Out" and "Future World" in the last encore segment of Helloween.

It was produced by Charlie Bauerfeind at Mi Sueño Studio on Tenerife and marked their return to the Nuclear Blast label with which they released The Dark Ride and Rabbit Don't Come Easy.

Although Hansen had been occasionally appearing as a guest on Helloween shows for a few years, Kiske had been particularly reluctant in interviews to the idea of performing with Helloween again due to bad blood with Markus Grosskopf and especially Michael Weikath, dating from when he was fired from the band in 1993; this started to change in 2013, when he ran into Weikath at the Sweden Rock Festival.

[52][53] He was cleared to perform by doctors in time for the next show in San José, Costa Rica on 23 October, although his illness forced the band to temporally remove a few songs from their setlist, and to have Deris, Hansen and Gerstner support him more vocally.

Like, after four weeks, like the middle of the tour, I was only able with huge glasses of red wine and painkillers to go on stage because my immune system was going nuts.

"[56] With regards to the taped vocals Kiske explained in a 2021 interview "I never did anything like that, and I will never do that again…When you do a playback, you've gotta be doing the same thing as on the recording, and I was, like, holding the microphone to the audience and my voice was coming through the P.A.

"[61] On 21 August 2018, the band announced that, at the request of their label Nuclear Blast, the Pumpkins United line-up would perdure after 2018, and that a live CD and DVD for the Pumpkins United World Tour would be released in early 2019, followed by a new studio album to be recorded later that year for a planned 2020 release, with Weikath, Hansen and Deris acting as a "songwriting trio"; this will be their first studio album to feature Hansen since Keeper of the Seven Keys: Part II in 1988 and the first with Kiske since Chameleon in 1993.

[65] On 26 November 2019, the band published a video in which they shared that they had begun recording their next album in Hamburg and that they were planning to resume touring in late 2020.