This is what we found on Wikipedia regarding the Abbath:

Olve Eikemo (born 27 June 1973), better known by his stage name Abbath Doom Occulta or simply Abbath, is a Norwegian musician best known as a founding member of the black metal band Immortal. Before founding Immortal, Abbath performed with Old Funeral alongside future Immortal member Demonaz. Following his departure from Immortal in 2015, he announced that he would be forming a new band under the Abbath name. Although primarily a guitarist, Abbath is also a proficient bassist and drummer, having started his career as a bassist and recorded all drums for Immortal albums Pure Holocaust and Battles in the North.