[4] In June 1984, guitarist and vocalist Thomas Gabriel Fischer and bassist Martin Eric Ain formed Celtic Frost after disbanding their previous band, Hellhammer, a month earlier.

While each contains elements of avant-garde composition, Into the Pandemonium is particularly noted for its unique style and experimentation with musical boundaries beyond the heavy metal genre.

Celtic Frost's next album, Cold Lake (1988), featured a new lineup and a dramatic stylistic shift, which was widely criticized for its commercial and flamboyant tone.

Celtic Frost drew inspiration from early heavy metal bands such as Black Sabbath, Judas Priest, and Venom, gothic rock acts like Bauhaus, Siouxsie and the Banshees, Christian Death,[7] and Joy Division,[8] as well as hardcore punk groups like Discharge[9] and GBH.

Metal Forces loathed the group, sparking a lasting feud between the zine and Warrior, which prevented Celtic Frost from performing in England for several years.

[11] Writers at Rock Power were similarly critical of Hellhammer, describing it as "the most terrible, abhorrent, and atrocious thing 'musicians' were ever allowed to record".

[13] Reflecting on the impact of his first band, Fischer said: Way back in 1984 and 85, when Martin Eric Ain and I recorded Celtic Frost's first two albums Morbid Tales and To Mega Therion, Hellhammer stayed with us almost like a curse.

Their 1984 debut EP, Morbid Tales,[15] was well received in the underground metal scene, and the band embarked on its first tour, through Germany and Austria.

The next of Celtic Frost's influential recordings was 1985's To Mega Therion, which did not feature Ain on bass, but instead used stand-in bassist Dominic Steiner.

The album is noticeably eclectic compared to the band's previous works, featuring love songs, industrial rhythmic pieces, symphonic and operatic influences, female vocal parts, and an unlikely cover of Wall of Voodoo's "Mexican Radio."

It marks a shift away from the heavier, more direct style found on the band's previous releases, Morbid Tales and To Mega Therion, although these albums also contained elements of experimentation and symphonic collaboration.

Into the Pandemonium blends a heavy metal foundation with elements of industrial and gothic rock, and even includes an electronic body music-inspired rhythm, particularly evident in the song "One in Their Pride."

Despite this stylistic evolution, the album retains sparse elements of extreme metal, noticeable in Fischer's vocals and guitar work.

Six months later, Warrior reformed the band, with Stephen Priestly returning on drums, Oliver Amberg on guitars, and Curt Victor Bryant on bass.

Despite being marketed to capitalize on the mass appeal of glam metal, the album was poorly received, failing to resonate with fans of the band's extreme style.

Several years after Celtic Frost disbanded, Fischer co-founded a new group called Apollyon Sun with his friend Erol Unala on guitar.

They initially headlined festivals (e.g., Wacken Open Air) across Europe and the United States/Canada in 2006, followed by the group's first-ever shows in Japan in early 2007.

Fischer stated that his new band would pursue a sound similar to the direction Celtic Frost took on their final album, Monotheist.

[20] In a 2021 interview with Heavy Culture, Tom Gabriel Fischer discussed the possibility of performing "one or two" Celtic Frost tribute shows in memory of Ain, featuring former members.

"[8] The online music website The Quietus published an interview with Fischer about his favorite albums, comprising a list of 13 notable influences.

[31] Other metal bands which have either cited Celtic Frost as an influence or covered Celtic Frost include: Darkthrone,[32] Entombed,[33] Tormentor,[34] Godflesh,[35] From Ashes Rise,[36] Repulsion,[37] Crowbar,[38] Integrity,[39] Rorschach,[40] Shai Hulud,[41] Deviated Instinct,[42] Doom,[43] Moonspell,[44] Anthrax, Obituary, Death, Benediction, Brutal Truth, Neurosis, Eyehategod, Cradle of Filth, Marduk, Dimmu Borgir, Goatwhore, Sepultura, Cancer, Asphyx, Pro-Pain, Gorgoroth, Gallhammer, Paradise Lost, Evoken, Napalm Death.

It too compiles a number of Celtic Frost covers by other bands, including Child Bite, Acid Witch, Municipal Waste, and Hayward, among others.

[46] In 2018, British deathcore band, Black Tongue covered the song "A Dying God Coming into Human Flesh" on their second album, Nadir which was released on Halloween of 2018.

[47] The hip-hop group "Circle of Tyrants" featuring Necro, Ill Bill, Goretex, and Mr Hyde also took their name from the Celtic Frost song.