I find strangeness fascinating, and this character is very strange, as is the world that he lived in and the way it is described here, in the Wikipedia. I offer a few excerpts:
Øystein Aarseth (22 March 1968 – 10 August 1993), who went by the pseudonym Euronymous, was a Norwegian guitarist and co-founder of the Norwegian black metal band Mayhem.
Dead [Per "Dead" Ohlin, his houseguest] committed suicide while alone in the house. He was found by Euronymous with slit wrists and a shotgun wound to the head. Before calling the police, Euronymous… photographed the body… One of these photographs was later used as the cover of a bootleg live album called Dawn of the Black Hearts.
Øystein called me up the next day ... and says, "Dead has done something really cool! He killed himself… Relax, I have photos of everything".
In time, rumors spread that Euronymous had made a stew with bits of Dead's brain and had made necklaces with bits of his skull.
Faust said "It sounds really silly, but I think there was a little bit of a contest between them to see who could be more evil
…a confrontation began, which ended with Vikernes fatally stabbing Euronymous. His body was found outside the apartment with 23 cut wounds…
It has been speculated that the murder was… an attempt at "out doing" a stabbing in Lillehammer by Faust.] Vikernes denies all of this, claiming Euronymous had plotted to torture him to death and videotape the event – using a meeting about an unsigned contract as a pretext. He claims that Euronymous planned to subdue him with a taser, tie him up, take him to a forest and use him to make a snuff film.
“I believe in a horned devil, a personified Satan… Satanism comes from religious Christianity, and there it shall stay. I'm a religious person and I will fight those who misuse His name. People are not supposed to believe in themselves and be individualists. They are supposed to OBEY, to be the SLAVES of religion.”
He said he would "Never accept any band which preaches Church of Satan ideas, as they are just a bunch of freedom and life-loving atheists, and they stand exactly the opposite of me".
Euronymous was a member of the Norwegian Communist youth group Rød Ungdom… he saw [his political leanings] as mutually compatible with black metal – influenced by the repressive nature of his Satanism as well as his intense misanthropy.