An episode from Supergirl season 5 may have featured a subtle return of a minor character from Arrow season 1. Debuting in 2012, Arrow was the flagship offering in The CW's ever-expanding universe of DC Comics-inspired shows. Starring Stephen Amell as Oliver Queen, the show proved to success for the network and spawned a host of direct spin-offs, including The Flash. Known colloquially as the Arrowverse, it also added the Melissa Benoist-led Supergirl to its ranks after it switched networks from CBS following its first season. Though Arrow officially concluded with season 8, the rest of the Arrowverse has already been renewed for new seasons.
Arrow season 1 largely explored Oliver's initial return to Star City and first steps into vigilantism. Simultaneously, flashbacks were utilized to depict the first year of his exile on the island of Lian Yu. Oliver wasn't the only one who seemingly died when his family's yacht sank, however. It was established that he was having illicit liaisons with Sara Lance, the sister of his then-girlfriend Laurel. Though Sara didn't even make it to the life-raft, Oliver's survival sparked an element of hope within the Lance family — most notably parents Quentin and Dinah. Their fixation on the idea that Sara might be alive was further fuelled by a photo of a similar-looking woman on neighboring islands in the area. In Arrow season 1, episode 18, "Salvation," Laurel tracked down the woman. Laurel introduced her to her parents as Jenn, revealing that she was nothing more than someone with a striking resemblance on a six-month sabbatical.
Played by Anna Van Hooft, the character of Jenn only appeared in that one scene and was never mentioned again. Like Sara Lance herself, however, the character may have just resurfaced. In Supergirl season 5, episode 15, "Reality Bytes," Van Hooft played a more prominent role. Ordinarily, that would mean little. Given the expansive nature of the Arrowverse — and how many years the shows have been on air — it's to be expected that an actor or actress would pop up more than once in different minor roles. What makes Van Hooft's appearance on Supergirl different and more significant, though, is the fact that her latest character was named Jennifer — of which Jenn is obviously short for.
The timeline of the character also tracks between the two shows. In Arrow, she made reference to needing to call her fiance. In Supergirl, meanwhile, Jennifer is not only married but has been married long enough for the relationship to sour. The result of that decline is what spurred on much of the action — with her husband, Richard, pursuing vengeance against the man with whom she'd been having a virtual affair. Given that the episodes are just short of a decade apart, that's more than enough time for such developments to have occurred. Though the Arrowverse has had its share of continuity errors, the choice in character name and these details imply that it's more than mere coincidence.
When Sara Lance did ultimately turn up alive, there was a prevailing theory that Jenn had been a decoy sent to throw her family off the scent. It was also speculated that Jenn might have actually been Sara and merely able to convincingly deceive them. Those ideas were lent credence by the fact Sara was trained by the League of Assassins and so would have easily amassed such skills of subterfuge. The reemergence of the character, however, implies that Jenn was at least her own character. Equally, despite Richard ultimately being drawn into Leviathan's machinations, it's unlikely that she will return and be revealed as in cahoots with one organization or other. As such, the overlap will serve mostly as an easter egg — as well as a subtle nod for how linked the respective cities of Arrow and Supergirl are now that the shows' respective Earths have merged.