Well, that's true. I just don't think he would so blatantly rip off another body of work. But in saying that he may well have been inspired. Vecna's ascencion is very similar to the Cowl's possible ascension.
Avernite - I always thought the Graiai were just another one of the Mother's mantles myself. But who knows?
Oh, I think so too, now - but the question to me is more, did the Graiai
start out as such, or were they slaughtered on the Stone Table to absorb the power/mantle into the Queens and/or their precursors?