Thanks to "Crisis On Infinite Earths", the Arrowverse can make Christopher Reeve's Clark Kent canon and treat the Kingdom Come version of the character as its primary Superman. So many different DC Comics shows, which were previously separate from the Arrowverse, are now becoming via "Crisis on Infinite Earths". But Christopher Reeve's Superman might possibly be the biggest addition yet -- if that's the direction the Arrowverse is taking.

The five-part event will feature five Arrowverse shows for the first time: The Flash, Arrow, Legends of Tomorrow, Batwoman, and Supergirl. This fact alone makes "Crisis on Infinite Earths" the biggest Arrowverse crossover to date, but that's not all. The scope of "Crisis" is proving to be bigger than the Arrowverse itself. Shows outside of the Arrowverse are getting some representation as well, as characters from Black Lightning, Birds of Prey, and Smallville are all joining in the fun.

Related: Supergirl Has The Most To Lose In Crisis On Infinite Earths

"Crisis on Infinite Earths" has so far assembled what looks like a DC fan's dream cast. The cast list boasts a long list of impressive names, including Robin actor Burt Ward from the 1960s Batman series, and longtime Batman voice actor Kevin Conroy as an older Bruce Wayne. The crossover also features new heroes like Osric Chau's Ryan Choi and multiple versions of the same characters. Due to the nature of the event, "Crisis" is using three Supermen, but which one is "Superman-Prime", or the best representation of the Superman from the comic books?

CW's Crisis On Infinite Earth's Supermen Are From Different Earths

"Crisis On Infinite Earths" pulls in characters from multiple timelines, including Earth-1, Supergirl's Earth-38, and more. Each show that gets incorporated into the crossover will most likely exist in its own universe. This also goes for the three different Supermen appearing in "Crisis", since there can be only one Clark Kent and one Lois Lane on each Earth. Based on what's been announced so far, the crossover has three Supermen and two versions of Lois Lane.

Legends of Tomorrow's Brandon Routh will pull double duty by playing The Atom and Superman. Routh portrayed the Man of Steel in the 2006 movie Superman Returns. Routh's character is said to be the "Kingdom Come" version of Superman. Also, Tyler Hoechlin will be back as the Arrowverse's original Superman. Hoechlin recurred as the Man of Steel in season 2 of Supergirl and reprised the role in last year's crossover, "Elseworlds", alongside Elizabeth Tulloch's Lois Lane.

Finally, Tom Welling will portray Smallville's Superman. The casting of Welling was perhaps the biggest news to come out of "Crisis" yet, as Arrowverse fans have been asking for a Smallville crossover for years. Welling will be joined by Smallville co-star Erica Durance, who will once again play Lois Lane. Smallville exists in a universe that's completely separate from all other Earths in the Arrowverse, since it contains many of the same characters, but each one of them is played by a different actor.

Related: Arrowverse Can Finally Have A Green Lantern (Thanks To Smallville)

Tom Welling Is Reprising His Smallville Character, Routh Is Probably Doing The Same

Brandon Routh as Superman in The CW's Crisis On Infinite Earths Arrowverse crossover event

Tom Welling played Clark Kent on Smallville for ten seasons, between 2001 and 2011. After eight years, Welling will play the same character again, and it's been confirmed that the crossover will explore what happened between Smallville's series finale and "Crisis". With both Welling and Hoechlin returning to play their respective versions of Superman, it may seem unusual if The CW brought in a third Superman legacy actor, and had him playing a completely new version, as opposed to his original role.

For this reason, it makes sense that Brandon Routh is playing the same character that he portrayed in Superman Returns. This could be true even though it's already been stated that Routh's character is the Kingdom Come version of Superman, who wears a different costume and exists in an alternate reality in the comics.

That being said, Routh's Superman Returns character and the Kingdom Come Superman can be the same person. In the Kingdom Come timeline, the staff of the Daily Planet (including Lois Lane) is killed by the Joker, who is in turn murdered by a vigilante before he can be convicted. When that vigilante is hailed as a hero, Superman becomes disillusioned and hangs up his cape. Several years later, Clark decides to resume his role as Superman and reform the Justice League. These events don't contradict Superman Returns, and could easily have taken place at some point after the movie.

Superman Returns Is Christopher Reeve Canon

Brandon Routh as Superman

Christopher Reeve starred as Clark Kent in four Superman movies beginning in 1978 and ending in 1987. Bryan Singer's Superman Returns is a sequel to the original films, but it ignores everything that happens in Superman III and Superman IV: The Quest for Peace. Superman Returns takes place five years after Superman II and continues the story of Reeve's Superman, but this time the titular hero is played by Brandon Routh instead. Routh was cast in part because of his "striking" resemblance to Reeve.

Related: Crisis Crossover Gives Brandon Routh's Clark Kent A Daily Planet Promotion

Superman: The Movie, Superman II, and Superman Returns all follow the same version of the character. So if Brandon Routh is playing his Superman, then that would mean that everything that happened in Superman: The Movie and Superman II is now part of the Arrrowverse. Having Superman: The Movie, one of the most celebrated superhero movies of all time in canon with all of its other shows would be a significant accomplishment for the Arrowverse.

Crisis May Be Treating Christopher Reeve As "Superman Prime"

Christopher Reeve as Superman standing in front of a city skyline.

Superman: The Movie is quite possibly the most beloved DC film ever made, and much of its reputation is owed to Reeve's portrayal of Superman. Since Reeve, numerous actors have worn the cape, and with every iteration, comparisons to Reeve are inevitable. This is because Reeve is generally viewed as the quintessential Superman. The level of respect that Reeve's Superman gets from fans and his status as the most important Superman on the big -- or small -- screen could lead to the Arrowverse giving the character the same treatment.

Also, photos of Routh in costume indicate that the character will be older than more traditional versions of Superman. With age comes wisdom, so of all three Supermen appearing in the crossover, Routh's character seems like the one who is most likely to deliver an inspirational, Superman-like speech. He may also be the one who leads the other heroes into action. All things considered, if the Arrowverse picks one of its three versions of Clark Kent to be its "Superman Prime", Brandon Routh's Kingdom Come Superman feels like the best fit.

More: Smallville Set Up Tom Welling's Crisis On Infinite Earths Role (In Season 11)