Mustis is the pseudonym of Øyvind Johan Mustaparta (born 10 September 1979), a Norwegian keyboardist best known for his work in the symphonic black metal band Dimmu Borgir, as well as the black/thrash metal band Susperia. Mustis joined Dimmu Borgir in 1998 and has contributed to the further progression of their ambient, atmospherical, symphonic sound. This can be heard in songs such as "Progenies of the Great Apocalypse", which he composed, on their 2003 album, Death Cult Armageddon. His other studio work with Dimmu Borgir includes Spiritual Black Dimensions (1999), Puritanical Euphoric Misanthropia (2001), the re-release of Stormblåst (2005) and In Sorte Diaboli (2007). Mustis departed the band in 2009 and issued a statement in which he implied that he was being kept out of the proper registration for music he was writing. Due to this, according to his statement, he was fired by text message and he will be allowing "the resolution come from the lawyers instead of dealing with more dishonesty and lies on a one-on-one personal level." Mustis' surname Mustaparta comes from Finnish language. Literally translated, it means "black beard". On 29 November 2010, Mustis posted the following statement on his Facebook fan page. "As you all can see I have no control over this site yet, but will try to get it soon as possible. If not..keep your eyes open for a new one. And thanks everyone for all the nice words in here. As you can see I decided to join my friends of Susperia where my first performance will be early next year. More info to come. In the... meantime you can always use google translate. -Mustis"