Warning: The following contains SPOILERS for The Flash season 8, episode 4, "Armageddon, Part 4."
The history of Ryan Choi, a.k.a. Atom following Crisis on Infinite Earths seemed to have been retconned significantly by The Flash Armageddon event, with the shrinking scientist now cynical about love. This was a far cry from his previous portrayal as a happily married newlywed and father of an infant daughter. While this could be explained as a side-effect of the Reverse-Flashpoint created by Eobard Thawne, it is strange that of all the heroes who appeared in "Armageddon, Part 4," only Ryan Choi saw such a significant change to his personal history and personality.
Ryan Choi was introduced into the Arrowverse during "Crisis on Infinite Earths: Part Three." A professor of physics at Ivy Town University, Choi was the only non-superhero revealed to be one of Crisis on Infinite Earth's Seven Paragons prophesized as saving the multiverse from the Anti-Monitor. While he was reluctant to get involved at first, even if it meant working with his idol, Ray Palmer, Iris-West Allen was able to persuade Choi to embrace his destiny for the sake of his family. Choi's wife and daughter were later confirmed to have survived and been reborn on Earth-Prime during the final chapter of Crisis on Infinite Earths.
A dramatically different version of Ryan Choi appeared during The Flash season 8, episode 4, "Armageddon, Part 4." This version of Choi, who had officially adopted Ray Palmer's Atom identity, said nothing about his wife and daughter during the episode. In fact, the version of Ryan Choi in the episode was reportedly something of a Don Juan. Further, he was the only hero present for the wedding of Flash's Iris West and Eobard Thawne who wasn't overwhelmed with romantic sentiment. He later admitted, however, that he was afraid of waking up alone every morning for the rest of his life.
While it is not impossible that Choi's life was changed in the new reality created when Reverse-Flash decided to create his own Flashpoint and rewrite time so that he became The Flash instead of Barry Allen, it is strange that his life would be changed so dramatically when nobody else's was. Batwoman Ryan Wilder made reference to her origin story, discovering the Batsuit after Kate Kane disappeared during a plane crash, and was living a life in line with her current storyline. Alex Danvers also seemed to be unchanged in the new reality, making reference to her own marriage, which occurred during the Supergirl season 6 ending and series finale.
It remains to be seen if this change to Ryan Choi's background will remain following reality being restored at the end of "Armageddon, Part 4." Longtime viewers of The Flash will recall that the original Flashpoint event made a number of small changes, including awakening Caitlin Snow's Killer Frost persona and changing John Diggle's daughter, Sara, into a son named John Jr. While it's possible that Ryan could go back to being the loving family man he was when he was introduced, it's also possible he might reenter the Arrowverse as the single scientist who had a relationship with the villain Giganta that he was in the original Atom comics.
New episodes of The Flash drop Tuesdays on the CW.