He is credited with largely helping in the formation of Black Metal, and evolving it from its thrash origins into what is identified as black metal today, and too creating the genre Viking Metal, the latter having a more evolved plus operatic style. He calm the melody plus wrote the lyrics on every one of Bathory's albums. Always underfunded, his albums had a rough quality which many black metal bands would afterward emulate, and which would come to typify this genre of music. He recorded in a garage, on a 4 track recorder, with mechanics working around him, and neighbors mowing their lawns, also recognized as Heavenshore Studios. The video was shown on MTV's Headbanger's Sphere, although he had not yet seen it at the occasion he was interviewed for the program.

He too played a bass guitar on approximately all of his albums, and mostly used a drum machine or a sitting drummer. First was called Book released in 1994, and Purity of Essence in 1997. While working on these albums he establish new inspiration to carry on composing music intended for Bathory.

But in 1996 Quorthon released Blood on Ice, a idea album which he began recording in 1989 but didn't finish. Blood on Ice returns to Bathory's viking metal method. His after that albums followed in so as to vein as did the Nordland saga. He was 38 existence old and was known to undergo as of heart evils.