Ok guys, thanks to Season 2, Episode 18 of The Flash, we have a whole lot of new evidence pointing to the identity of Zoom's padlocked prisoner. If you haven't seen the episode, absolutely catch up before you continue, because SPOILERS ABOUND!
Have you watched it? Fantastic! Ok, let's start at the beginning — the origin of Hunter Zolomon.
The Horrifying Zolomon Family Tragedy
We now know just how similar Zoom and Barry really are and the crucial detail that set them on their different paths. While Barry always knew his father was innocent in the murder of his mother, Hunter never had any such luxury. His father murdered his mother just a few feet from him and made him watch.
With his mother dead and father imprisoned, Hunter was shuffled through the foster care system. We don't know much else about how Hunter grew up; we're almost immediately informed that he later became a serial killer. Convicted of 23 murders, he was committed and endured electroshock treatment up until the Star Labs explosion infused him with the Speed Force.
Ok, what does that tell us? On its own, not too much, but there were a couple of key lines in the episode that helped define the difference between Hunter and Barry.
What Family Means to the Speedsters
After Cisco re-opens a breach to Earth-2, Zoom and The Flash race through Central City before Zoom is trapped in Star Labs. Face-to-face, the two throw a few verbal jabs, during which Zoom remarks that family is a weakness. It's a circumstantial truth: To him, "family" is a psychopathic father and a murdered mother. To Zoom, 'family" has only ever meant pain.
But to Barry, "family" isn't just his mother and father. Family is Joe, it's Iris, it's Caitlin and Cisco. To Barry, family is love. Both of these — pain and love — are the driving forces behind the two metahumans, and that's where things get interesting.
Every Crime Has a Motive
When Zoom first arrives through the re-opened breach, he notes that Cisco has increased his power. Barry responds with: "Hate is a powerful motivator." That struck a chord with me. We know that Zoom hates weakness, and as we see him encounter the pictures of his family in Star Labs, the effect it has on him is clearly a detrimental one. It causes him to lose focus and he lets his guard down. For someone like Zoom, that's a massive problem.
So how could a murderous speedster keep himself motivated and remind himself of why he does what he does? Pictures of his family won't do, of course; seeing them as if they live a normal life knocks him for a loop. But what if Zoom were able to get the real thing? Not his mother obviously — she's long dead. But as far as we know, his father is still in prison. For The Fastest Man Alive, getting his father out would be a cinch.
What better way to motivate yourself than to physically cage your first and greatest weakness to remind you every single day where you came from and where you are going? And if you can't bear to look at your weakness face-to-face — or you can't bear to hear their voice — there's an easy fix: Use a mask.
Now this is all just a theory. Zoom himself answers a query in this episode about the identity of the man in the iron mask with: "You wouldn't believe me if I told you" and he revealed he's found at least one other version of himself from a different time. The man in the mask could be another Hunter Zolomon, or maybe someone no one has guessed yet. But from what we learned about Zoom this episode, my money is on the man who started Hunter on his dark path.