The sound on Fra Underverdenen moved away from some of the folk aspects that were featured on band's past releases and concentrated more on Thomas' fondness for classical music.

Their 2006 album Kvass was recorded between November 2005 and January 2006 with producer Rune Jørgensen in Silvertone Studio in Gamle Fredrikstad.

In 2010 Kampfar went to the famous Abyss Studio in Sweden to record their next album Mare with producer Peter Tägtgren.

Long serving guitarist Thomas quit the band even before the album was released and was replaced by Ole (Mistur, Emancer) for the upcoming live shows.

Ole later joined the band permanently and Kampfar went on to tour Norway, North America and Europe twice to support the album.