Lee Thompkins’ ongoing transformation from hero to ambiguous maybe-villain is an intriguing part of Gotham Season 4, considering that it directly flies in the face of both the original character in the comics and her portrayal until this point. But post-Tetch virus, she’s been embracing her dark side, possibly building to Lee becoming Gotham's Harley Quinn. It would be a surprising choice, as some fans were totally convinced that it was Barbara, not Lee, who was on her way to becoming the iconic DC villain.
But, now, into Season 4, there's been confirmation that Barbara will not become Harley. Gotham star Erin Richards told Showbiz Junkies, "She was changing at the end of the last season, and we had some ideas of who she could change into. And that certainly sounds like the series was heading towards transforming Barbara into Harley Quinn. However, sometime between Seasons 3 and 4, Richard told the same outlet, the plans changed. "Then we decided that it would be better that she just remains herself," she said.
However, with Babs out of the running after being brought back to life by Ra's al Ghul, Lee certainly seems like a woman worth considering as the next Harley suspect. And if you think about it without all of the Barbara distractions, there have actually been several big hints that it's Jim's other ex-girlfriend who could become the famous DC villain.
First things first: Lee is a doctor, and so is Harley. This clue is so obvious, Lee should have been Gotham's chief Harley suspect long ago. Granted, in the continuities where Harley is a doctor, she's a psychologist, while Lee is an MD, but both started their careers at Arkham Asylum with the intent to help the downtrodden. And through the machinations of a truly terrible boyfriend (in Harley's case, the Joker, in Lee's case, Jim), they went from slightly naive to villainous. (Well, Leslie definitely seems to be on the way there anyway.)
Here’s another factor, though: Lee isn’t much of a killer, nor does she have a particularly strong relationship with the clownish aesthetic that’s sweeping some parts of the city as a result of Jerome's influence. However, Lee was once exposed to Jerome, and forced to help him sew his dismembered face back on (yeah, Season 3 really went there). Jerome's not quite the Joker in Gotham, and her brushes with him aren't quite the same as forming a deeply unhealthy and psychologically dependent obsession with him, like Harley does. But if Gotham was trying to leave some clues for Lee's eventual turn to Harley, consider them detected.
It's possible that now that Cherry has been killed, Lee might take over as boss of the Narrows’ resident fight club, which would make a harlequin style pretty appropriate. Lee's current dark and unfriendly mood doesn't match Harley's manic energy in her TV and movie appearances, but perhaps she'll grow more comfortable in this situation over time, and begin to take more joy out of it. Gotham has played the long game with Jerome, so they could definitely be doing that with this character as well.
It's a viable theory for sure, but here's the biggest and most obvious hint that Lee will not become Harley: she's already another character adapted from DC comics. The Lee from the source material is totally different than the Gotham version, but she's definitely a part of the canon. DC's Dr. Leslie Thompkins has been a part of DC lore since 1976, and she's never had an arc where she becomes a villain. Instead, she's usually an older woman who is close friends with Alfred and the deceased Wayne parents.
So Gotham would be the first place that Lee Thompkins could not just go bad, but become a different iconic character from the mythology. She's already changed so much since her arrival; maybe her next step is one that will shock and hopefully delight long-time fans of the comics.