Question: Which Norwegian black metal band invited Attila Csihar from Tormentor to do vocals on their first full-length studio album?
Sentence (from "Tormentor"): Following the suicide of Per Ohlin, Mayhem invited Attila Csihar from Tormentor to join the band; he was to perform the vocals on "De Mysteriis Dom Sathanas".
Relevant evidence: Yes