Norwegian black metal musician, multi-instrumentalist, and vocalist. He is also known under stage names Aggressor, Czral and Exhurtum. He has played in various black metal and avant-garde metal bands. These include Ved Buens Ende, Aura Noir, Cadaver, Dødheimsgard, Satyricon, Ulver, Infernö and recently the jazz/rock band Virus. His drumming is unusual in style, with very little repetition and a tendency to shy away from traditional drumming.