Am I wrong, or did they say from the start that the villain was going to be a known one from existing Trek lore?
If that's the case, I don't know of any Trek villain named "Harrison".
Do any of you?
This means either:
1) my memory is playing tricks,
2) they've changed their intention, or
3) Harrison actually IS someone else, whose name will become known before the end of the film.
(If not, and they wait for a later film to reveal who he really is, that's sort of strange since it will leave the "return" of a villain from TOS up in the air...it'll be hollow if we still don't know who he is.)