Richard Cobbett brought up a new area where AoC might offend some of the more religious people in the population in his online journal. The Stygians, the infamous followers of Set, love demonic magic. And when we say love demonic magic, we really mean that they can turn into demons if you're a Herald of Xotli or summon demons if you're a Demonologist. The word Stygian can even be translated as "dark" or "infernal".
While this is pretty tame for those of us who are into fantasy settings, it's just another part of where AoC can be offensive to those around it. Funcom has no doubt pushed the envelope with this game, but as any good Conan fan will say, "It's just another normal day in Hyboria."