[WARNING: This article contains possible SPOILERS for The Flash!]

The minds behind the writing, casting and marketing of The Flash had earned the right to be coy with their plans for the show's second season, having introduced the DC Comics hero's most iconic enemy (with a new, crowd-pleasing twist). Instead, they unveiled their plans months ahead of the premiere, teasing even more Speed Force drama for Barry Allen, since "Zoom was coming."

Now Zoom has arrived, and his plan is clear (even if the motivations behind it are not): send a number of metahumans from a parallel Earth into Barry's version of Central City, and hope one of them can succeed in killing "Earth-1"s resident super speedster. But the real question, and on fans are used to asking, is who is really under the villain's black mask? With his hatred for Barry and Jay Garrick still a mystery, Zoom's real identity may be the key to understanding what the writers have in store.

Theories are easy to come by, so we thought we would take what's been revealed in the show, along with the decades of Flash mythology from the comics, and offer our own. Here are 5 possible answers to the question: Who is Zoom?

The Rival

We'll start with the most obvious, or at least, the simplest explanation. With every Flash comes a polar opposite speedster, usually quick to take up the mantle of "the Reverse-Flash" (subtlety isn't really their thing). And while he may not be as famous as the enemy of Barry Allen or Wally West, Jay Garrick's own nemesis, 'The Rival' proved to be just as much of a nightmare.

Unfortunately for fans of expanding time travel loops or universe-hopping, the Rival's story is a straightforward one: after Jay Garrick's science experiment gave him super speed, a professor by the name of Edward Clariss tried to recreate the results. Using a formula to grant himself the same speed, Clariss set out to defeat The Flash, eventually traveling too close to the speed of light, and entering the Speed Force completely, eventually driven insane and murderous by his time in its depths.

It wouldn't be the most shocking revelation for Jay Garrick (Teddy Sears) to realize that 'Zoom' was just a maniac imitator, but the show has offered some clues. For starters, Zoom emerged not long after Jay gained his speed, he wears a black, identity-concealing uniform, and leaves trails of blue lightning. Again: obvious, if not world-shattering.

The Black Flash

Less a theory, and more of a clarification here. Considering how many viewers will be researching "a black Flash" in the coming months, it's worthwhile to explain the nature of the character actually known as The Black Flash in the DC Comics universe. In a comic book mythology where the real, the surreal, the supernatural and the mystical coexist, the Black Flash acts as something of a Grim Reaper - the physical embodiment of Death for those channeling the Speed Force.

When a speedster is close to death (whether ill, risking absorption into the Speed Force, or taking on too dangerous a challenge), the Black Flash appears as a harbinger of their demise. The actual identity of the character, if they are more than a symbol - usually depicted as a skeleton in a Flash costume - hasn't been explored, but Barry Allen has taken up the job in the past (to his dismay).

So even though the show seems to imply that it really is a human being underneath that suit, the color, the mystery, and the fact that Zoom is out to kill every speedster he comes across means it's hard to ignore the theory. If nothing else, it may be a sign that the show's writers are paying tribute to The Black Flash since they can't actually introduce a Grim Reaper in their universe.

Cobalt Blue

Perhaps more accurately, 'Cobalt Blue... or some variation thereof." Even serious DC fans may not remember this villain, since his origin story is more than a little contrived (in the way only comic books can be). As Barry Allen learned as an adult, he was actually one of a set of twins born to his parents. But when a drunk doctor couldn't save the baby of another couple in the same hospital, he decided to even thing s out: let the Allens believe only one of their twins survived, and give the living twin to the other family: The Thawnes. You can see where this is going.

Malcolm Thawne, as the boy was named, grew up in a family of con artists who used a mystical blue flame to heal (and swindle) the desperate - a power Malcolm didn't possess. When he eventually learned why he was different, and his brother Barry Allen enjoyed a far better life, he learned to use the blue energy for evil, taking the name Cobalt Blue, and setting out to destroy The Flash.

Ever since the show introduced Detective Eddie Thawne (approximately the same age as Barry), fans have theorized that Eddie would one day be revealed as Barry's brother, making him Cobalt Blue even without the codename or powers. Add the fact that Eddie wasn't killed, but simply sucked into the singularity formed in the season one finale, and there's still reason to think a Thawne other than Eobard could be pulling the strings to torment Barry.

Barry Allen

Maybe we're just fans of symmetry, but now that the door has been opened to parallel universes and alternate versions of each human being, the possibility that Barry will go up against himself has to at least be discussed. When Jay Garrick and Martin Stein (Victor Garber) explained the basic parallels between their Earths, they noted that each person could, conceivably, have a doppelganger on the alternate planet.

It seems strange that Barry wouldn't even consider aloud the idea that Earth-2's Barry lived happily with both parents... or was that version also the victim of an alternate Reverse-Flash? As fans have seen, Barry Allen went through enough trauma to break any child, and owed his character and determination to the people around him: his adopted father Joe, his adopted sister, and his friends at S.T.A.R. Labs. Could things have worked out differently?

The comics have shown a Barry driven to extremes before, even in alternate timeline stories where he seems more villainous than truly heroic. It may be a far-fetched idea, but it would definitely take fans by surprise.

Joe West

If 'Zoom' is the name of Wally West's greatest enemy, and Wally's time as Barry's successor probably won't be chronicled on The CW show, then the writers are clearly deciding to try something different. And if that's the case, why not do it with one of the only original characters created for the show? Sure, Joe West (Jesse L. Martin) is a loving, devoted father on Earth-1... but could things have worked out differently for him in another life?

Consider just how many mysteries surround the character: what happened between he and his wife? What would his life have become if he hadn't been called upon to raise Barry along with Iris? What if, as explicitly stated in "Flash of Two Worlds," the parallel Earth's version of Joe West was a far cry from the upstanding detective fans know and love? He's likely not a cop, since Jay hasn't heard of him.

The emotional sucker punch that The Flash's twists tend to carry would be taken care of with Joe revealed as villain, not to mention a clever way to bring his Earth-2 child (Wally, perhaps?) into the fold. Exactly how Joe came by his speed, or his desire to kill speedsters is up for debate. Jay was unclear about what caused his powers - perhaps it came at a price (that Joe, not Jay had to pay).

As far as theories go, we think Joe being the one under Zoom's glowing mask (he's the right size, after all) is one of the more thrilling ideas to entertain. Especially with Zoom looking for ways to kill Barry Allen, and the sudden return of Iris West's mother. Coincidence? We'll be waiting to find out along with every other fan.

Conclusion

Those are just a few of our theories on the true identity of Earth-2's Zoom, but we invite any and every fan to weigh in on our predictions, as well as adding their own to the conversation. Have we hit the nail on the head, or do you think we missed the most likely candidate? Sound off in the comments!

Next: 10 Jay Garrick Facts Flash Fans Need to Know

The Flash airs Tuesdays @8pm on The CW.