User blog comment:Pualover/Overlord Power Level/@comment-5480911-20151022164116/@comment-1846146-20151027082339

Yes. Elder Lich can cast tier3 spell Fireball, and that's their limit. Thus lvl range 21-27 (1 tier per 7 lvls logic) Also Zero is around lvl 24-27, and Davernoc is weaker than him, so even less - 21-24 lvl. Also Iguva-41 was created by Ainz with Necromancy amplification, and still lvl 22, and with special abilities lvl 30, so basic range should be less. 21-24 should be correct answer.