The Arrowverse’s Crisis on Infinite Earths crossover changed the fate that Smallville season 3 set up for Tom Welling’s Clark Kent. Like the comic book character, Smallville’s version of Clark Kent did become the hero he was destined to be, but his Crisis on Infinite Earths cameo revealed that his superhero activities ended within a decade.
When the Arrowverse’s Superman (Tyler Hoechlin), Lois Lane (Elizabeth Tulloch), and Iris West (Candace Patton) went to Smallville’s Earth to recruit Clark, they reached a shocking discovery. To start a family with his version of Lois Lane (Erica Durance), Clark gave up his Kryptonian abilities for good. Apparently, Clark is now experiencing the normal life of a human running Kent Farm, and seems to be satisfied with the path he chose for himself.
The newspaper clippings at the beginning of the episode confirmed that Smallville’s Clark fulfilled the destiny he was always intended to have by saving the world several times as Superman, but his story didn’t have the ending that was previously set up. In the season 3 episode, “Hereafter”, Clark and his friends met Jordan Cross (Joseph Cross), a meteor-infected student with the ability to see how people die just by making physical contact with them. When he touched Lana Lang (Kristin Kreuk) for the first time, for instance, he saw her die of old age, but when he touched Clark, he saw no end at all. Instead, he just saw Clark’s Superman cape flying through space, which served as a tease of his future. When he told Clark about it, he said “it’s like you live forever.” Clark seemed a bit unnerved by the possibility.
The idea that Clark might possess immortality was reinforced by a similar vision that Doctor Fate received in season 9’s Justice Society event. Not only that, but Martian Manhunter (Phil Morris) did tell him once that he’d outlive all his loved ones. Jonathan (John Schneider) also considered that this might happen, since they didn’t really know that much about Clark’s limitations at the time. What all of these things pointed to was that Smallville’s Superman would have a long and lonely future ahead of him. But ahead of the Crisis, Clark prevented this fate from ever coming to pass when he presumably used gold Kryptonite to get rid of his powers, thus allowing himself to age naturally.
However, it’s worth noting that Smallville’s immortality teases don’t make Clark’s Crisis on Infinite Earths ending a plot hole. “Hereafter” proved that the future isn’t set in stone. Multiple deaths foreseen by Jordan were averted by Clark, and according to him, Clark was the first person to ever do this. As noted by Martha (Annette O’Toole) and other characters throughout the series, Clark is capable of changing fate. So if he can alter the destinies of others, it stands to reason that he can change his own fate as well.