There is no concrete information on the band members, only rumours. The main one is that Hasjarl and Shaxul teamed up to form Deathspell Omega after the split of Hirilorn in 1998. Mikko would have eventually joined the band on vocals in 2003 for the recording of SMRC and onwards to replace Shaxul who left because of the growing Orthodox Satanism elements.

Hasjarl is the owner of End All Life Productions and one of the main guys behind Norma Evangelium Diaboli.
Mikko Aspa is the owner of Northern Heritage and Freak Animal Records (power-electronics label).
Shaxul (ex member) is the owner of Legion of Death Records.

DEATHSPELL OMEGA items we have:

Orthodox black metal.