You know, about the part about Anarkin/Vader being the most powerful force user ever, that wasn't concieved by GL when he made the OT right? The only time Vader's past was mentioned was in EPVI when the spectre of Obi-wan told luke that when he first met Anarkin, the latter was already an exceptional pilot or something.
When did Anarkin recieve his messianic role?