Question: Future World" is a song and a single made by the German heavy metal band Helloween, it is performed frequently by Helloween and which power metal band from Hamburg, northern Germany, founded and fronted by Kai Hansen after his departure from the German power metal band Helloween?

Context paragraphs:
Pink Bubbles Go Ape: Pink Bubbles Go Ape is the fourth studio album by German power metal band Helloween, released in 1991.  It marked the departure of guitarist Kai Hansen, with Roland Grapow replacing him.  Musically it was written with a softer, less epic, and sometimes humorous approach, which would be later fully implemented in the band's following album "Chameleon" (1993).

Sole Survivor (Helloween song): "Sole Survivor" is a song and a single made by the German power metal band Helloween taken from the album "Master of the Rings".  On "Closer to Home", the lead vocals are sung by Roland Grapow.  The song has been covered by the Swedish power metal band Dragonland on their third album 'Starfall'.

Keeper of the Seven Keys: Part I: Keeper of the Seven Keys: Part I is the second studio album by German power metal band Helloween, released in 1987.  It marks the first appearance of vocalist Michael Kiske, and is considered the album that created the genre of European-style power metal.  Kai Hansen stepped away from doing vocal duties as he had difficulties singing and playing the guitar at the same time during the previous tour.  It was an album dominated by Hansen, due to an injury to co-guitarist Michael Weikath which prevented him from performing on much of the album. " Future World" was released as a single and a music video was made for "Halloween" but with 8 minutes omitted from the song.  The band originally planned to release "Keeper of the Seven Keys: Part I" and "" as a double album, but their record label refused, insisting that the albums be released separately.  Much later in 2010, both albums were released together with bonus tracks.

Michael Kiske: Michael Kiske (born January 24, 1968) is a German singer best known as the lead vocalist for the German power metal band Helloween.  After his departure from the band, Kiske recorded four solo albums, participated on various metal and rock related projects, such as Avantasia, Place Vendome and Kiske/Somerville, while he also performed with numerous bands as a guest vocalist.  In late 2009, he formed the hard rock / heavy metal band Unisonic and began touring again after 17 years of absence.  On November 14, 2016 it was officially announced that Kiske will tour again with Helloween and Kai Hansen in 2017 and 2018.

Helloween: Helloween is a German power metal band founded in 1984 in Hamburg, Northern Germany by members of bands Iron Fist and Gentry.  Its first line-up consisted of singer and guitarist Kai Hansen, bass guitarist Markus Grosskopf, guitarist Michael Weikath, and drummer Ingo Schwichtenberg.  After the release of a self-titled EP and their debut album "Walls of Jericho" in 1985, it expanded into a quintet with the addition of singer Michael Kiske, Hansen choosing to focus on guitar instead.  Under this line-up, they released the "Keeper of the Seven Keys" albums (1987 and 1988), which established Helloween as a notable heavy metal band and led to the creation of the power metal subgenre.  However, Hansen left the band quickly after the release of "Part II" and was replaced by Roland Grapow.  He then created the band Gamma Ray.

Future World (Helloween song): "Future World" is a song and a single made by the German heavy metal band Helloween taken from the album "".  It is performed frequently by Helloween and Gamma Ray at their concerts, and is usually used for crowd participation, usually with the crowd singing the first verse, sometimes after the singer shouts the first phrase.  Also there is a certain "game", that when the band jams, the singer signals the crowd to shout: "We all live in future world" a few times near the end of the song.

If I Could Fly: "If I Could Fly" is a song and single made by German power metal band Helloween, from their album "The Dark Ride".  The song begins with a grand piano that combines itself with distorted guitars and pounding drums.  The lyrics depict a man in a journey of self-discovery.  The song was written by Helloween frontman Andi Deris.  The song has become one of Helloween's most popular, joining Future World, I Want Out and "Eagle Fly Free" on their live setlists.  It was released in some countries as "If I Could Fly".  In Japan, it was released as "Mr. Torture".

Gamma Ray (band): Gamma Ray is a power metal band from Hamburg, northern Germany, founded and fronted by Kai Hansen after his departure from the German power metal band Helloween.  Hansen is the current lead vocalist, guitarist as well as the chief songwriter of Gamma Ray.  The band is known as one of the most prominent bands of the German heavy metal scene.

Kids of the Century: "Kids of the Century" is a song and single by the German power metal band Helloween taken from the album "Pink Bubbles Go Ape".  This is the first Helloween single with Roland Grapow playing guitars, replacing Kai Hansen.  It is also the first Helloween recording with a song written by bassist Markus Grosskopf: "Shit and Lobster".

Roland Grapow: Roland Grapow (born 30 August 1959 in Hamburg, Germany) is a professional guitarist and music producer.  Grapow is best known for his time in the leading power metal band Helloween, who he played with for 12 years after replacing founding member Kai Hansen.  He subsequently created the power metal band Masterplan in 2001, which is still active today.

Supporting paragraphs: Future World (Helloween song) Gamma Ray (band)
Answer: Gamma Ray