/jp/ - Otaku Culture

Question for more knowledgeable fatefags, is Irisviel as we see her at the end of Fate/Zero and in Unlimited Blade Works just Angra Mainyu using her appearance as a mask to emotionally manipulate Kiritsugu and Illyasviel and Irisviel's consciousness has long since been destroyed, or is that her actual personality having been corrupted by the grail (kind of the impression I got by the end of the end of Fate/Zero episode 22)?
I know some of this is anime-original (namely the UBW scene) and that Irisviel in general is a character made after the original Fate/Stay Night, but surely something in the lore clarifies.