Brandon Routh’s return to the role of Superman in Crisis on Infinite Earths makes him one of several Men of Steel in the series. Not only this, but it looks like he'll essentially be playing two different versions of the character mashed together. Routh first played Superman in Superman Returns, which was a continuation of the "Donnerverse" Superman movie series. His costume in Crisis also looks just like the aged Superman from the Kingdom Come comic book world, but producer, Marc Guggenheim recently confirmed that he IS, in fact, an aged Donnerverse Superman, by way, it seems, of Kingdom Come.
With this in mind, let's look at who the Kingdom Come Superman is, and how the Donnerverse's Last Son of Krypton could have ended up as a similar character to Alex Ross and Mark Waid's dark future iteration.
KINGDOM COME'S SUPERMAN
The world of Kingdom Come, along with that of The Dark Knight Returns, exists as one of DC’s go-to "dark future" stories. In the former, the Justice League has retired and, in their place is a new generation of violent, arrogant heroes who leave nothing but destruction in their wake. This was caused by Superman being the first to hang up his cape after the Daily Planet was attacked by a geriatric Joker. The Clown Prince of Crime kills the Daily Planet staff, including Superman's wife Lois. Before Superman can apprehend Joker, the clown is killed by Magog, a violent anti-hero who sees Superman's methods as outdated. The world at large agrees, and the shifting tide in public sentiment and morality causes Superman to exile himself.
Superman's very visage is also different in this bleak tomorrow. Though aging much slower than a human, the Man of Steel's face is still more weathered, with his temples also beginning to grey. This is still a far better physique than the Batman of Kingdom Come, who, after years of physical abuse, is forced to have a supportive exoskeleton surgically attached to his body for simple movement in his old age. This hardened and utterly defeated approach to DC's two biggest heroes reflects the aim of the story's themes: Kingdom Come was a response, if not attack, on the more violent and far less traditional heroes of the '90s that were popularized by characters such as Marvel's Cable and Image Comics' entire horde of initial "heroes." Thus, the brokenness of the old icons reflects them seemingly being passed by the new, young upstarts of the comics industry of that era.
SUPERMAN FALLS
For the most part, there was no suggestion in Superman I – IV or Superman Returns that this world had any other prominent heroes in it besides Superman himself, meaning that trying to meld the Kingdom Come storyline with the Donnerverse isn't going to be an exact fit. This is compounded by the fact that Clark Kent will be the Daily Planet's current Editor-In-Chief by the time of Crisis, making even more unlikely that Joker or any other villain attacks and kills the paper's staff. It is possible, however, that Lois Lane is dead, potentially at the hands of Lex Luthor rather than Joker, preserving one of the key elements of this version of Kingdom Come Superman without tying it to unintroduced versions of other characters or making the future seem too bleak for the lighter Donnerverse.
The premise of Superman Returns could itself lend extra tragedy to the possible loss of Lois Lane. The film revealed that, after the events of Superman II, Lois had become pregnant with Superman's child. The boy was initially believed by most to have been the child of Lois and her fiancée, Perry White's nephew, Richard. Eventually, however, Jason White's true paternal lineage becomes clear when he easily throws a piano at one of Lex Luthor's henchmen to protect his mother. To keep from revealing his identity and intimate past with Lois, as well as allow her to go on with Richard, Superman essentially abandons the child to human parents and doesn't tell him the truth. This writing decision was somehow far less controversial than what Man of Steel and the DCEU did with the character, notably tainting the wholesomeness of the Donnerverse.
Plans for a sequel to Superman Returns would have likely involved Brainiac (Kryptonian in origin, like on Superman: The Animated Series) following Superman to Earth and possessing Jason. Brainiac would bring world-changing Kryptonian technology to the masses, making the world question and shun Superman for not having done the same earlier.
This pariah status mirrors that of Kingdom Come Superman and, given that it seems Superman would have had to eventually choose between the life of his son and the lives of everyone on Earth, the writers of Crisis could easily use tap into this abandoned idea to give their version of Kingdom Come Superman similar heartbreak, tying together the Donnerverse, Kingdom Come and Superman Returns.
"Crisis on Infinite Earths" begins Sunday, Dec. 8 at 8 p.m. ET/PT on Supergirl, then continues in Batwoman on Monday, Dec. 9 at 8 p.m. ET/PT and in The Flash on Tuesday, Dec. 10 at 8 p.m. ET/PT. After the winter hiatus, the crossover will conclude on Tuesday, Jan. 14 in Arrow at 8 p.m. ET/PT and in DC's Legends of Tomorrow at 9 p.m. ET/PT.