| milura |
well kind of simple answer here:
your paladin willingly does all the evil to become a graveknight, as such stops being a paladin and becomes an evil undead. no problem so far.
but once you are a graveknight why on earth would you want to have atonement cast on you? you are an utterly evil creature with no reason to feel sorry for what you have done. It would take some very convincing roleplay and a damn good reason why you would ever get an atonement. likely when you go asking for it you'll get killed on the spot before you can even explain what you want.
important line from atonement : "This spell removes the burden of misdeeds from the subject. The creature seeking atonement must be truly repentant and desirous of setting right its misdeeds."
so while you can become a graveknight, going back to paladin is very unlikely, since you won't want to go back. going anti-paladin would be so much more logical