Worlds will collide in December with "Crisis on Infinite Earth," The CW superhero crossover that will not only follow through on the promises, or threats, of last year's "Elseworlds," but will also be instrumental to the farewell to Arrow and Oliver Queen. Based on DC's 1985-1986 comic book event, "Crisis" will feature the cosmic entity the Anti-Monitor as a villain so powerful that it will require the assembled heroes of the Arrowverse, Black Lightning, Lex Luthor and no fewer than two versions of Superman, for starters. The event's premise, with parallel worlds in danger, permits notable cameos by the likes of Burt Ward and Kevin Conroy, but it also opens the door to the introduction of new characters -- say, like the ruler of Apokolips.

Now, there's no indication that The CW has any plans for Darkseid, who was part of Zack Snyder's original vision for Justice League and its abandoned sequel, but one cosmic threat deserves another. Here are some reasons why "Crisis On Infinite Earths" should include Darkseid, and perhaps why it should not.

Darkseid Is ... Powerful

Darkseid is easily one of the most powerful beings in the DC Universe, and has defeated Superman himself. Thus, that he would team up with not one Superman but two to confront the Anti-Monitor would demonstrate just how formidable the villain of "Crisis" is. Although the Arrowverse has no version of the New Gods, introducing them in some capacity -- even a minor one -- would showcase the size, and the scope, of the threat faced by the heroes.

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Darkseid's only live-action appearance to date was in the final season of Smallville, in which his portrayal was notably criticized by fans. By including Darkseid here, however briefly, The CW could redeem itself, giving fans the version of Uxas of Apokolips they expected in 2011. (It's worth noting persistent rumors that actors from Smallville will appear in "Crisis.")

Release #TheCWCut

Darkseid was also meant to appear, in some capacity, in Snyder's original version of Justice League, recently confirmed through concept art. The odds of a Snyder Cut utilizing these unproduced elements is slim at best, so The CW would be giving fans a character that the movies couldn't. Again, this would easily make "Crisis" one of the biggest TV events of 2019.

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Crisis On Infinite Rules

The biggest issue preventing Darkseid from appearing in "Crisis" is the rather inconsistent Warner Bros. rule about character use. While the studio allowed two Flashes to appear simultaneously on the big and small screens, Batman isn't permitted to show up on Batwoman, and Deathstroke can only menace Arrow ... until he can't (but Batman and Deathstroke can appear on DC Universe's Titans).

While Darkseid was, as mentioned, hasn't appeared in any live-action films, he is destined to play a role in Ava DuVernay's upcoming New Gods. That may result in limitations to where else the rule of Apokolips can be used.

There's also the question of budget. Darkseid's majestic presence would have to look good, especially given the negative reception to his portrayal on Smallville. Although special effects have certainly come a long way since 2011, the network may not want to strain the budget for what is surely an already-pricey crossover.

Nevertheless, Darkseid's use in "Crisis" would not only reflect the source material, but also top off what should be hours of fan service.

"Crisis On Infinite Earths" kicks off Sunday, Dec. 8, with Supergirl, and continues Monday, Dec. 9, with Batwoman, Tuesday, Dec. 10, with The Flash, Tuesday, Jan. 14, with Arrow, and concludes Tuesday, Jan. 14, with DC's Legends of Tomorrow.

KEEP READING: What Roles the Arrowverse Heroes Played in DC's Crisis On Infinite Earths