Who Are the Mysterious Figures At The End of Supergirl's "Medusa" Episode?

While most eyes were focused on the start of the three-episode, four-show crossover "Invasion!" this week, Supergirl had its own midseason finale to deal with, seemingly putting the threat of Cadmus on the back burner to deal with a more pressing danger in the form of...

...wait, spoilers ahead for last night's midseason finale episode of Supergirl, titled "Medusa."

...in the form of alien invaders, hell-bent on finding Mon-El.

And no, it doesn't appear to be Dominators, the alien race tied to "Invasion!" in both the comics and on TV. They will play a role on Supergirl later this season, but for now, the shadowy, cloaked figures seen at the end of the episode seem to be something else.

Why? Well, first of all, the Dominator craft seen in numerous TV spots for tomorrow's episode of The Flash looks nothing like the ship seen ferrying the cloaked figures about.

Intriguingly, there was another race that formed part of the Dominators' core of invaders in the Invasion! comic book series, and those characters could pass for the cloaked, faceless beings seen at the end of "Medusa." That would be the Durlans.

A race of shape-shifters, the best-known Durlan is of course Chameleon Boy of the Legion of Super-Heroes. But while his look is a distinctive one, the Durlans of the 20th Century had gotten so used to shapeshifting that they literally forgot what they were "supposed" to look like and ultimately ended up as hooded space beasts with a Cthulu-like visage.

With the Legion of Super-Heroes already established in the mythology of Supergirl (a Legion ring has been spotted in the Fortress of Solitude in the past, suggesting that Superman likely has had experiences with them), ties to the Durlans wouldn't be totally out of left-field...and the fact that the Dominators will make their way to Supergirl's world soon enough could suggest that elements of the Invasion! comics that don't make it into this week's crossover are fair game.

That said, it doesn't feel right.

There's a particular Superman-related story that has been referenced a number of times this season, and there's very little to lead us to believe that it might not be where the second half of the season is headed.

We'll start with "Isotope 454," the chemical MacGuffin from tonight's episode of Supergirl, which as we noted in our Easter egg hunt was likely a nod to The Adventures of Superman #454.

During Superman's self-imposed Exile in Space, which took place just after the Man of Steel killed General Zod and two other Phantom Zone Kryptonians in a Pocket Universe, the last leg of his journey came when Superman was found drifting in space and kidnapped by slavers affiliated with Mongul and Warworld. Realizing that Superman was a Kryptonian, and thesefore potentially quite powerful, they forced him into gladiatorial combat against Draaga.

Interestingly, Mon-El earlier in the season told Supergirl that he had seen Draaga fight on Warworld.

Throughout the course of the Warworld story arc, Superman learned that his ancestors had been part of a mission to "purify" Krypton by exterminating clones and aliens -- a mission that went horribly awry when they also ended up coding a failsafe into Kryptonian DNA which would eventually prevent them from being able to leave the world when it was destroyed.

The Warworld chapter of Exile started in Adventures #454.

A variation on that theme was delivered last night, of course, when Supergirl learned that her father had helped to build Medusa, the alien-killing virus that Cadmus was working to weaponize against National City.

Combine this with the look -- oddly shaped, with bits of the body shot through with light -- of the ship helmed by those mysterious aliens last night and a theory starts to come into focus.

Below you can see the ship from "Medusa," paired with a couple of different shots of the craft that carried Superman to the moon where he would first encounter Mongul before the games on Warworld.

There's also a generally yellow-ish look to the craft in several shots, althoguh that could just be that it's a dark or black ship against the backdrop of space and a spectacular aurora effect.

In any event, one perfectply plausible theory seems to be that the ship is indeed coming from Warworld.

After Superman defeated Mongul in the comics, he refused to either kill those he defeated or assume the throne of Warworld, and that affront caused a number of characters -- including Mongul and Draaga -- to chase after him to get their due. They followed him to Earth, where he would have to battle them on their terms.

What if having "seen a battle" on Warworld wasn't just a bit of color for Mon-El's character, but an important piece of backstory? It doesn't seem totally unrealistic that he could be on the run from Warworld after escaping.

Who would the aliens be, then? Well, with their features so obscured it's virtually impossible to make an educated guess, although one could reasonably speculate that the female who did most of the talking could be Mongal, the daughter of Mongul, who took over for him briefly after his death in the comics. Giving a female, physical big bad would be a pretty obvious direction for Supergirl to go, and she would fit with a lot of the mythology and bits of background that's been sprinkled into the show so far.

Got a better theory? Sound off in the comments below!