The Flash Season 2: 7 Theories On The Man In The Iron Mask's Identity
3. Earth-2 Henry Allen
Although there had been some suggestion about Earth-1 Henry Allen being first Zoom, and later our iron-masked friend, that seems rather impossible given his reemergence in the past couple of episodes. But it doesn't rule out Earth-2 Henry Allen from the latter.
This is a character who was mentioned but never seen, and the last we know he was supposedly on holiday. Convenient. The thing that's most working in the favour of this theory, though, is when Earth-1 Henry mentioned that Garrick was his mother's maiden name.
That surely can't go unaddressed, and must have some sort of role to play in things. Could it mean that Earth-2 Henry is actually Jay Garrick, and thus the Flash on that world was Barry's dad (which would mean John Wesley Shipp playing a version of the Flash again). Barry saw the original 90s Flash in the Speed Force, and maybe this is why.
It'd fit with being mind blowing, and it could have some strong emotional connection to Barry that would fit with Kevin Smith crying over it.