Swedish metal band Ofermod has its roots in black metal, but its members currently refer to their own music as "Orthodox Qliphotic Death Metal" in an attempt to de-emphasize the satanistic associations of the former term in favour of more complex occult themes present in their later work.

The group was originally a solo project in 1996 by guitarist Michayah, who at that time called himself Belfagor and was also active in the band Nefandus. In 1997, vocalist Nebiros joined the band. The duo entered Necromorbus Studios in January 1998 and recorded a 7" EP entitled "Mystérion Tés Anomias" which was released later that same year in 500 copies through PMP (Pounding Metal Productions). Bass player Mist left the band in 1999.

After this, the band went on hiatus for several years, due both to Michayah's wish to get away from the "scene" and to some legal problems. In 2004 the band was re-formed with Shiva (a.k.a. Necromorbus) on drums. The previously-recorded EP was remastered and re-released through Norma Evangelium Diaboli in 2005 with two new tracks added and recorded in December 2004. These were recorded with a new line-up, which together with Michayah and Nebiros consisted of guitarist Atum and bass player Tehôm, both previously in the band Dödfödd. During 2005 the line-up of the band increased with the additional vocalist Moloch.

In March 2006, Michayah was sent to prison for assault, robbery and some other charges. He was released in August, but was taken into custody a few days later, and sentenced to serve more time due to additional acts of violence. This delayed the release of the new album, which was partly finished in late-2005/early-2006 under the longstanding working title "Pentagrammaton" before finally seeing a 2008 release as Tiamtü.