I’m not a StarWars buff by any means (I like the films and all, but I’ve always been a Trekkie), so I’m very late to the party here but...
TIL that “Darth Vader” literally means “Dark Father” (English “Darth”, Dutch “Vader”) so the “twist” was signposted from the start! 
I presume he's getting Darth from "Da'ath" the Hebrew sephira on the Tree of Life. It's the one sphere which is 'secret' often not drawn.
