God I always hated the DnD morality system. Arthur is certainly not Chaotic, he wants the empire to rule the world because nation states create wars and wars kill people.
As for Evil, eh, probably? I'll be making sure his goals are relateable at least, and his reasons marginally sound, though "absolute world domination-enforced peace" could be called evil depending on what school of thought you subscribe to. It is certainly a bad idea if you ask me. Not sure it's evil.