The Flash Season 2: 7 Theories On The Man In The Iron Mask's Identity
4. Earth-1 Or 2 Eddie Thawne
Eddie was one of the favourites to be Zoom, which shows a couple of things. 1) These theories can be way off (just sayin'...), and 2) People feel Eddie has some unfinished business.
The former is still true, but the latter less so after recent weeks, given we've already had Earth-1 Eddie reappear (via flashback) and provide closure to Iris. The show poignantly closed that chapter, so would they reopen it?
Well, maybe. His appearance would just about fit, and in terms of his doppelgänger, we didn't see him on Earth-2 - maybe he's a speedster or someone of importance over there. Or, tying into Zolomon's message of "you wouldn't believe me" it could even be Earth-1 Eddie, brought back to life by a combination of time-travel and narrative necessity.