Volothamp Geddarm's persona has been adopted by a devil that killed him in secret and hired out its services as a sort of evil PR expert. This is why Volo's Guide to Monsters gives excuses for every classic evil mook race, even though one would think if it was all a god's fault (Orcs, Goblins) or if they never did anything wrong unless they were forced into it (Kobolds) they wouldn't be evil in the first place.