Leviathan was formed in 1998 by Wrest. In Leviathan, Wrest records and plays all instruments including vocals entirely on his own. Additionally he has collaborated with the band Sunn O))) and is an active member of the band Twilight, as well as playing and recording everything in Lurker of Chalice.
Unlike many solo black metal bands, Wrest plays kit drums as opposed to using a drum machine and has stated in interviews that he has been playing drums longer than any other instrument and that the drums are his instrument of choice.