"I never asked Arms that question; is it important to discuss it now?" Gaven found the question utterly meaningless, whether it was innate or an acquired replacement, it was all the same.
"To you, perhaps not, but to me, it's very important." Grace said solemnly, "Arms raised me, taught me. If, from the beginning, he was being impersonated by an Evil Beast Spirit, then so be it. But if the real Arms was replaced halfway through, where did the real Arms go?"
"You probably won't get an answer to that question," Gaven said helplessly, spreading his hands, "That Evil Beast Spirit has been completely destroyed by me; not even ashes remain. There's simply no way to answer your question."
Daphne suggested from the side, "There is an indirect way to verify this, and that is for you to perform the Complete Resurrection Spell to try to revive Arms, to see if it is possible to get a response."