WARNING: This article is speculation but also has some unrevealed facts in it that may be viewed as spoilers for The Flash so don't say I didn't tell you so.
There has been a lot of speculation on the internet as to who Zoom may be. Various fan theories have been cast around, so I thought I'd share mine and see what everyone thinks.
History of Zoom
The name Zoom in the comic books was accredited to a reverse flash by the name of Hunter Zolomon and rather than being a Barry Allen villain he was a Wally West villain. In the comics he just like Eoabard Thawne wore a yellow suit with a backwards red lightning bolt. His powers also weren't quite like other flashes/reverse flashes as he didn't draw on the speed force for speed but rather altered time relative to himself so other speedsters would in some circumstances appear to be running in slow motion compared to him.
Now it could well be that the show writers have stuck with the original source material (after all Wally West has already been cast for season 2) or it could be someone else. Let's take a look at a few other possibilities
Henry Allen Earth 2
Now I'm sure by now everyone has heard a theory on how Henry Allen could be Zoom, or at least seen a variant of the above picture. The look and build of him and Zoom are very similar. Granted they don't sound the same but Harrison sounded nothing like the Reverse Flash, and Barry sort of distorts his voice too. Plus if you look at the old pictures of him as The Flash from 1990 and imagine his suit black and covering his face a bit more they do look pretty alike. Also if you look at the scene where Flash hurls lightning at Zoom in slow motion when it misses him slightly and lights up his suit as it goes past (as he only seems to show up in the dark) his suit appears a bit more of a dark red, whether that's a trick of the light or not I'm not sure, but i could be that his suit is dark red and appears black because he only appears at night or under low lighting. But asides from looks here is a theory I've come up with for Henry Allen as Zoom
On the season finale of The Flash we saw Barry running through time and space through a wormhole allowing him access to visions from other time periods (possibly even of other earths if not just he goes to earth 2 later in the season) and at one point we see Barry Allen in jail. Now we all know that on Earth 2 things are a lot different with everyone, Jay is the flash not Barry, Harrison Wells is just Harrison Wells not Eoabard Thawne in disguise (that we know of) and Oliver Queen died on board his dad's boat and Robert Queen was the one to survive (maybe to become Earth 2 Green Arrow?). So what if instead of Henry going to prison, Barry did. Being in prison at the time he was away from the particle accelerator blast and instead Henry became the speedster. But unlike Barry he didn't have a comforting guiding hand to help him grieve and when given superspeed he became morphed and became a beast-like creature by his hatred and anger that had built up over the years and he used this speed he had acquired to hunt down all other speedsters as he had acquired a hatred for all of them after one killed the love of his life and got his son sent to jail for it. Also on one episode I remember Harrison Wells saying he used to be human, implying not only has he not always been like this but he may know who the person was before. And as we know Zoom is holding his daughter captive so if he knew it was Henry Allen, father of Barry Allen even from another world he wouldn't tell Barry as it may make him hesitant to attack or show remorse, when Harrison wants him to pay. Also his powers although faster than Barry's seem to look virtually identical rather than time altering and when hit with the speed dampener from Cisco it seemed to affect him which if they weren't like Barry's powers it may not have done.
I realise there are a couple of holes in this theory as it's early days and I may be clutching at straws so let me straighten a few things out.
Eoabard Thawne may have killed Nora on Earth 2 to get at Henry rather than Barry as maybe in their timeline Henry was supposed to become the flash (after all Robert Queen maybe Earth 2 Green Arrow). As to why Barry would be blamed over his dad I'm not exactly sure. It could also be that Barry killed her for real (disturbed child or an accident) and Henry went mental and used his powers to inflict pain on others but in order to do that he had to remove other speedsters and heroes from the equation.
I'm also not sure where Eoabard would be if he's not in Harrison Wells' body so to speak if he was the one that killed Nora
Now I know John Wesley Shipp's Henry Allen has the build etc for Zoom but the suit design and everything about him screams black flash. For a start his suit is black (duh). Secondly we have the weird mouth thing on CW's Zoom looks like it's doing a mimic of black flash's but not to the fully twisted extent that the comics do. thirdly there's the claws. The only real difference (and it is a minor one) is the lighning bolt. It's the same way round as The Flash's, not inverted like Reverse Flash's and is red not black, but so far he looks the most like him by a long shot but again we can't go on looks alone
The Black Flash essentially fulfills the same role as Death for those who possess super-speed in the DC Universe, returning them to the source of their powers: the Speed Force. It is reportedly seen before the deaths of Barry Allen and Johnny Quick; Max Mercury, having had several near-death experiences, has also seen the Black Flash. It is not clear whether the Black Flash exists because the speedster characters are simply too fast for traditional Death to capture, or as some sort of bizarre side-effect to their connection to the Speed Force. On The Flash Zoom seems to has an obsession (as Jay points out) with killing all speedsters. He doesn't necessarily care about taking other lives although he's not bothered who gets hurt in his mission to kill everyone connected to the speedforce.
The drawback with this theory is twofold on this. Black Flash has always been the Black Flash (from what is known) and didn't start off human. He also had an easy opportunity to kill Barry recently when he beat him like a ragdoll almost to death then paraded him round Central City in typical VILLAIN fashion, like someone with an ego and/or a point to prove rather than just a function of nature. Just like Eoabard who could have killed Barry as a child or when he was in a coma from the lightning strike or anytime really, instead he wanted to build him up to his peak condition then kill him. In a similar fashion Zoom seems to want to discredit The Flash first rather than go in for an easy kill by parading his half dead body round town first.
Eoabard Thawne AKA Reverse Flash Earth 2
What if on Earth 2 Thawne came back to kill Nora Allen, but didn't go home, or take over Harrison's body but rather bided his time waiting until The Flash was given his powers and then follow through with Earth 1's Thawne's plan to go home and got hit by the particle accelerator which sort of juiced up his already fast powers and as a result sort of dismorphed him a bit hence the slight beast-like look he has going on and ability to be faster than other speedsters. Also on Earth 2 his beef may not have just been with Barry but with all speedsters hence the speedster killing spree Zoom so wishes. Or maybe the extra power made him go mad with power and the one thing people with power want who have power is more power. Power corrupts and absolute power corrupts absolutely sort of thing. After all Jay claims Zoom took his speed from him (how is still unclear)
Eddie Thawne Earth 2
Love him or hate him he saved the day in the end on Flash Season 1 finale by sacrificing himself. However when he did he was sucked into the singularity and his body being dragged through a rip in time and space could do anything to him. Bit of a longshot but he could be following in his great great (etc) grandson's footsteps. Barry did take the love of his life after all and going through the rip may have twisted his biology and not only brought him back to life but fuelled his hatred
Cobalt Blue has a different suit to suit (but at this point who doesn't) but the blue that eminates from him in the form of a flame could be translated to the small screen to blue lightning. But it's not all about looks like I've stated before and he does have some similarities. Going back to the Season finale when Eoabard's time machine was being constructed they were going to use tungsten I think it was and decided to change to Cobalt so that it didn't melt or something either way Cobalt was mentioned. The Wormhole that opens up and pretty much all of the CGI in that scene was blue. Cobalt and Blue. Could be a coincidence or maybe a subtle hint.
Cobalt Blue's History: On the stormy night of May 13, two pregnant women came to the office of Fallville, Iowa's Dr. Gilmore. However, the doctor had been drinking, and he had sent his nurse home. The child of one of the women, Charlene Thawne, had been strangled on its own umbilical cord, and Gilmore was too intoxicated to save the poor baby. However, the other woman, Nora Allen, successfully gave birth to twin boys. Gilmore, trying to be fair, gave one of the twins to the Thawne family, telling the Allens that one of their children had been stillborn. The twin that remained with the Allens was named Barry, and he grew up to be the Flash. The other twin, however, was raised by the Thawnes, and he was named Malcolm.
When he was older he learned he was adopted and grew a hatred for Barry, and even saw the incident that gave him superspeed. He uses a talisman to draw on for his speed. He draws the superspeed from it by draining it from speedsters. Now it is possible that he isn't even from earth 2 he is from another and has drained power from another speedster then gone to earth 2 to take on Jay then to Earth 1 for Barry. We know Zoom can steal speed as he has taken Jay's. Plus we may have already seen the talisman before on a certain body that got sucked into the singularity.
Now when I first saw it round his neck I suspected it could be the engagement ring for Iris but it's not if you look closer the middle is filled in and does indeed look like it could be a talisman. This picture could also support the Eddie Thawne theory as well.
And finally, an unusual one but it would be a smack in the face
Barry Allen Earth 2
Now this would definitely be a plot twist but what if Earth 2 was the evil speedster there. After all his suit isn't a reverse flash suit the lightning bolt is facing the same way as flashes and the general design (apart from mouth) is similar. Like I mentioned earlier it may not be black as such either it may just be very dark red. I also mentioned that Joe was a nurturing guiding presence for Barry and in a recent episode Barry asks Joe if he would have turned out the way he would without him. I mean if you think of the amount of Metahumans in Central City that have been discovered so far and the ratio of heroes to villains is certainly stacked in favour of getting powers makes you a supervillain. Earth 1 Barry was raised by Joe and he was brought up to be the loving caring person who runs towards danger to protect others. Now what if Joe wasn't present for whatever reason on Earth 2. Maybe Barry became a product of the foster system bouncing from home to home, or got uncaring parents or was at the very least not encouraged and helped like Joe did then his obsession he has about his mum's death may drive him to kill and/or drain speed from all speedsters either with a blind hatred for all speedsters after learning about Reverse Flash or maybe even so he can gain enough speed to catch Thawne and end him.
So there are a couple of theories - who do you reckon Zoom could be?