Warning: Spoilers ahead for the season finale of Supergirl, titled "Nevertheless, She Persisted."
After being poisoned by a device that bombarded National City's atmosphere with lead, Mon-El of Daxam was forced to leave Earth, and Supergirl lost the boyfriend who has been a key part of her life this season.
The development comes in the season 2 finale, titled "Nevertheless, She Persisted," and sets begs the question: will Mon-El return at a later date as part of the Legion of Super-Heroes?
With the introduction of a Phantom Zone Projector in the Fortress of Solitude last week, ComicBook.com speculated that Mon-El would be stranded in the Phantom Zone, waiting to be discovered in about a thousand years by the Legion. That's been a popular fan theory all season -- that ultimately Mon-El wouldn't stay on Earth or return to the stars with his mother but that he would likely get injured at some point and end up in the Phantom Zone.
Instead, he headed to space in the same capsule that had brought him to Earth from Daxam -- with his fate unclear, especially after something that looked like a portal into the Phantom Zone opened up and swallowed the craft.
In the comics, it was lead poisoning that led Mon-El of Daxam to be placed in stasis in the Phantom Zone, until he could be recovered and cured in the 30th Century by the Legion.
Back in December, DC released a video detailing their top ten Legion of Super-Heroes stories, couched in the context that with Mon-El appearing on Supergirl, "the Legion of Super-Heroes can't be far behind."
While it's questionable at best for fans to immediately leap to the conclusion that DC All Access has enough of an "in" with the TV side of things to read that line as a solid confirmation, it's also probably naive to assume that DC spending money to produce a video featuring a team that's currently without a regularly-published comic doesn't mean something.
The Legion of Super-Heroes is a team of teen-aged superheroes from a thousand years in the future. Headquartered on Earth, they come from a variety of different worlds and have a variety of different powers (although each of them wields a Legion flight ring, which provides its wearer with a universal translator, the ability to fly, and some other perks).
Inspired by the legend of Superboy, the Legion traveled back in time to recruit Superman as a teenager, and would periodically steal him away to the future to have adventures with them, returning him to Smallville when they were done. At different points, the post-Crisis on Infinite Earths Superboy (Conner Kent) and Supergirl have also been part of the Legion.
Once one of DC's most successful and popular franchises, the Legion of Super-Heroes have suffered quite a bit since the first line-wide continuity reboot following 1986's Crisis on Infinite Earths. At that time, Superman's backstory was modified so that he was never Superboy and the Legion had to modify its own backstory to accommodate, "invalidating" many of the stories that pre-Crisis Legion fans had loved. The character who took Superboy's place in those retroactively-altered tales, though? Mon-El, the Daxamite hero often known as Valor.
While he did have his own ongoing series set in the present day for a while, and participated in the World of New Krypton storyline which also took place in the then-current DC Universe, most of Mon-El's memorable stories have taken place as part of the Legion of Super-Heroes, so when he came on board, many fans wondered whether it was just a matter of time before we would see the rest of the Legion.
That impression was rooted, in part, in the fact that fans have already seen evidence that the Legion not only exists in the world of Supergirl, but has a relationship with Superman. In the season 1 episode "Fortress," Supergirl headed to Superman's Fortress of Solitude for the first time and one of the first things the audience saw was a Legion of Super-Heroes flight ring mounted on a crystal dais inside.
SUPERGIRL is an action-adventure drama based on the DC character Kara Zor-El, (Melissa Benoist) Superman’s (Kal-El) cousin who, after 12 years of keeping her powers a secret on Earth, decides to finally embrace her superhuman abilities and be the hero she was always meant to be. Twelve-year-old Kara escaped the doomed planet Krypton with her parents’ help at the same time as the infant Kal-El. Protected and raised on Earth by her foster family, the Danvers, Kara grew up in the shadow of her foster sister, Alex (Chyler Leigh), and learned to conceal the phenomenal powers she shares with her famous cousin in order to keep her identity a secret.
Years later, Kara was living in National City and still concealing her powers, when a plane crash threatened Alex’s life and Kara took to the sky to save her. Now, Kara balances her work as a reporter for CatCo Worldwide Media with her work for the Department of Extra-Normal Operations (DEO), a super-secret government organization whose mission is to keep National City – and the Earth – safe from sinister threats. At the DEO, Kara works for J’onn J’onzz (David Harewood), the Martian Manhunter, and alongside her sister, Alex, and best friend, Winn Schott (Jeremy Jordan). Also in Kara’s life are media mogul Cat Grant (Calista Flockhart), James Olsen (Mehcad Brooks), a photo journalist who moonlights as Guardian, a masked vigilante, Lena Luthor (Katie McGrath), and Mon-El of Daxam (Chris Wood), whose planet was ravaged by Krypton’s destruction. As Kara struggles to navigate her relationships and her burgeoning life as a reporter, her heart soars as she takes to the skies as Supergirl to fight crime.
Based on characters created by Jerry Siegel and Joe Shuster, SUPERGIRL is from Berlanti Productions in association with Warner Bros. Television, with executive producers Greg Berlanti (“The Flash,” “Arrow”), Andrew Kreisberg (“The Flash,” “Arrow”), Sarah Schechter (“Arrow,” “The Flash”), Robert Rovner (“Private Practice,” “Dallas”) and Jessica Queller (“Gilmore Girls,” “Gossip Girl,” “Felicity”).
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