Warning: spoilers ahead for the Supergirl Season 2 finale, "Nevertheless, She Persisted."
Season 2 of Supergirl has officially come to an end, and what an end it was! The finale pulled out all the stops, bringing back Superman and M'gann M'orzz and Cat Grant to help Kara and the D.E.O. to save the day from the Daxamite invaders. Despite Rhea's attempt to double cross Kara after they engaged in single combat, Kara and her pals were able to stop the Daxamites by flooding the Earth's atmosphere with enough lead to kill every Daxamite on the planet. Thanks to his months under the yellow sun of Earth, Mon-El survived long enough to escape on his pod. All things considered, the episode was a win for the good guys.
That said, the episode also dropped hints at some terrifying bad guys of DC Comics fame who could definitely pop up and menace the Girl of Steel in Season 3. Check out the four villains we have reason to believe could definitely appear!
The cliffhanger of "Nevertheless, She Persisted" was a flashback to the destruction of Krypton, 35 years prior to the Daxamite action of present day. It featured a group of mysterious robed figures preparing a baby for transport. One of the figures brushed the baby's face with blood, which made it pretty clear that this was a future villain we were dealing with. The baby was then tucked into a rocket and sent away by the hooded Kryptonians, who said that "it" would reign over the Earth someday.
In DC Comics canon, Doomsday was the product of cloning experiments by a Kryptonian scientist looking to create the perfect weapon. Given that the hooded figures on Krypton in the Supergirl finale were clearly hiding their actions from the Kryptonian public, it stands to reason that what they were doing was sketchy, and what could be sketchier than using cloning to try and create a perfect biological fighting machine? The baby sent to Earth could very well be a young Doomsday, who would be quite grown up by this point in the Supergirl chronology. The pieces fit, and this baby could definitely be Doomsday.
While Mongul himself hasn't yet been mentioned on Supergirl, episodes have hinted at his existence. Earlier in Season 2, Mon-El casually mentioned attending the gladiatorial games on Warworld, which is best known as in DC Comics lore as the roaming artificial planet control by the brutal Mongul. An alien gladiator by the name of Draaga appeared in the very same episode, and Draaga was a key character in early comic interactions between Superman and Mongul. Then, in the Season 2 finale, Superman himself revealed that he has actually been to Warworld, even learning a special fighting move there.
The first mention of Warworld could have been an Easter egg incident for DC fans, and the second reference with Draaga could have been more or less a coincidence. The third and more obvious mention of Warworld points toward an appearance from the legendary villain who hailed from that terrible place: Mongul. At this point, it'll simply be disappointing if Mongul doesn't attack Supergirl or Superman at some point in the series.
Last week's episode of Supergirl on the reveal that Queen Rhea had somehow brainwashed Superman into doing her bidding. He only appeared for a few seconds in the episode, but it was already clear after he gave Kara a serious smack across a room that he didn't know what he was doing. In "Nevertheless, She Persisted," we learned that Rhea was using something called "silver kryptonite" to convince Superman that Kara was actually the villain General Zod, whose appearance in the episode was actually a hallucination.
There's actually not much comic canon basis for silver kryptonite at all, but such a substance was used on Smallville to debilitate Clark in the same way that he was on Supergirl. The silver kryptonite on Smallville was created by Brainiac. Supergirl has been known to cherrypick its canon from various DC sources; perhaps this silver kryptonite was created by Brainiac, just as it was with the same effects on Smallville.
The mystery baby from the Season 2 finale cliffhanger most obviously points to Doomsday, who is one of the most high-profile DC Comics villains thanks to how often he has been featured in movies and TV shows. That said, Supergirl could be going with a lesser known villain with a surprisingly similar origin story to Doomsday: Reign.
The villainess Reign is a fairly new addition to DC, having made her debut in 2012 as the product of Kryptonian experiments that involved altering alien embryos in order to create powerful living weapons. The project that created her was abandoned when she was very young, leaving her to develop without guidance. Reign crossed paths with Supergirl, and they two quickly became bitter enemies.
If I was a betting woman, I would put my money on Reign as the mystery baby who was shot off in the pod in the Season 2 cliffhanger. Supergirl could probably get more mileage out of a villain who hasn't already been done to death on other shows and movies, and the show does tend to pit Kara up against female villains. Besides, given Reign and Kara's comic connection, even comic fans couldn't complain if Reign was brought in as the Season 3 supervillain. I'm guessing that there might be some controversy from diehard DC fans if Doomsday was turned from a traditional Superman villain to a Supergirl villain.
I'd definitely love to see Mongul as well at some point, even if it can't be in Season 3. Supergirl has teased Warworld enough times that I'll be pretty bummed if we don't get to see this show's unique take on it and its leader. We'll have to wait and find out.
Unfortunately, we still have a while to wait. Supergirl won't return to The CW until the fall. Stay tuned to CinemaBlend for the latest in TV news, and don't forget to check out our summer TV premiere schedule to discover all your viewing options now and in the coming weeks. Be sure to drop by our rundowns for cable/streaming and broadcast TV renewals and cancellations as well. Our TV season finale schedule can give you all you need to know about your shows ending.