There's more than one artist under this name:
1. Thorns (formed as Stigma Diabolicum, but changed name to Thorns after two years) is a Norwegian black metal band, masterminded by Blackthorn (Snorre W. Ruch - also in Mayhem and Satyricon). They made two highly influential demos in the early 90's, Grymyrk and Trøndertun, but have only released one full-length album, since the band was founded, in 1989.

Read more about Thorns on Last.fm.