Keep of Kalessin spawned back in 1994, under the name Ildskjaer, by Ghash and Obsidian C., later joined by Vyl and Warach. The band's violent yet dark and epic black metal as well as the somewhat mysterious moniker and lyrics, are inspired by the work of fantasy of the American writer U. Le Guin "The Earthsea Quartet".With this concept in mind, the guys recorded the first demo Skygger av sorg in the fall of 1996, though several problems in finding a proper rehearsal room made this task rather difficult and as a matter of fact the lack of practice resulted in an untight performance on tape and a consequent limited spreading of it. Only some ten labels and magazines received it and the response was surprisingly positive, gracing the band with a contract from Italy's Avantgarde Music. The debut album Through Times of War was recorded in summer 1997 in Brygga studios, Trondheim and presented the band with a crystal clear yet heavy production on some ear-blasting music which has been often compared to Mayhem's opus De mysteriis. A couple of years later, after some pretty successful gigs played around Norway together with Bloodthorn, the quartet returned with "Agnen. A journey through the dark", again recorded in the much appreciated Brygga studio.With this second album the band actually took much distance from the now trendy Norwegian Black metal style, picking up influences from the thrash and death metal genres thus establishing a rather Swedish oriented sound. But the guys did not forget their roots and therefore they took part in the much anticipated Mayhem tribute album released by Avantgarde itself. Their superb interpretation of "Buried by Time and Dust" put them right up there with the likes of Emperor, Gorgoroth, Dark Funeral, just to name a few of the top class bands also appeared on this ambitious project.

In the year 2000 the line-up split due to personal reasons, but guitarist and songwriter Obsidian C. wouldn't let that stop him. He continued to make Kalessin-style music and developed his own style even more. This ultra-fast, brutal and yet melodic style needed a drummer, but in the small town of Trondheim he was unable to find one that could keep up with his riffing. Almost three years would pass and then he was offered the job in Satyricon after he had auditioned and played the ass off some 30 other guitarists from all over the world who had applied for the job. As soon as he was a part of Satyricon he was also in contact with one of black metal's fastest and most brutal drummers, Frost!

Frost heard the new Keep Of Kalessin material and immediately said yes when Obsidian C. asked him to do the drumming on his new EP. Touring with Satyricon also made it possible for Obsidian C. to recruit the legendary Attila Csihar who did the vocals on Mayhem's De Mysteriis dom Sathanas. The three piece line-up recorded the Reclaim EP, released in 2004 and put the band into the elite black metal scene of Norway, but due to the distance between Frost, Attila and Obsidian C. this line-up couldn't last. Obsidian C. is determined to bring Keep Of Kalessin to the masses and has seen that live performances is a must for doing that. He has teamed up with early Kalessin drummer Vyl and found a perfect replacement for Attila as well as a new bass player.

Together with the lyricist from the Reclaim EP, Torstein Parelius, Obsidian C. has for the past two years been working on the new album entitled Armada.

This album is anticipated to bring Keep Of Kalessin even further into the elite ranks Norwegian metal along with bands like Emperor, Satyricon, Immortal, Mayhem and Dimmu Borgir.

The album will be a huge epic masterpiece which will be a massive blow to the worldwide metal scene. It is melodic, but it's still fast and grim and every song on the album is said to bring goosebumps from top to toe!

A new video will be released in early 2006 and the album will hit the stores worldwide on March 27th.

The album Kolossus was released in May 2008 and the band was touring extensively for a couple of years including support for Dimmu Borgir and Behemoth on their US tour in 2008.

In 2010 the band again broke new ground when they participated in Melodi Grand Prix, the national edition of the Eurovision song contest. The band shocked everyone when they won the first regional final and reached as far as 3rd place in the national final. With this participation the band reached far outside of the metal community being A-listed on Norwegian radio and being talked about constantly in the mainstream press.

In May 2010 their latest offering Reptilian was released to standing ovasion from all metal media. The album went straight into number 2 on the Norwegian charts and was also doing well in both Europe and US. This also resulted in extensive touring reaching around 200 shows in support of the album in both North America and Europe. The band also did their first South American show in front of 800 crazy fans.

Currently the band has decided to calm down on the touring, but are already working on a new album which will be released in October 2012.

In 2013, the band released a new video alongside announcing the firing of long time vocalist Thebon for "disappearing into Africa for 5 months with no word" and that instead of replacing him with a new member that Obsidian C. himself would be taking over as the new vocalist.