Supergirl has cast Jessica Meraz as the DC Comics antihero Pamela Ferrer aka. Menagerie, a character typically associated with the antihero Manchester Black. The latter made his debut on The CW TV series in the ongoing season 4, where he's portrayed by actor David Ajala.
Prior to next week's Arrowverse Elseworlds crossover event, Supergirl aired its 2018 midseason finale and set the stage for what's to come when the show proper continues in January. The midseason finale - titled "Bunker Hill" - concluded with both Manchester Black and Ben Lockwood (Sam Witwer) aka. Agent Liberty being arrested for their respective crimes and taken into custody at National City Jail. At the same time, Supergirl was forced to quit the DEO after she refused to reveal her secret identity - despite being commanded to do so by U.S. President Baker (Bruce Boxleitner) - in the wake of Lockwood's capture. Suffice it to say, this won't be the last we see of Black nor hear of Lockwood and/or the anti-alien movement that he helped to set in motion.
Case in point: Deadline reports that Meraz will join Supergirl's cast in 2019 as Menagerie, a character who's part of Manchester Black's "Elite" in the DC Comics universe. The "Elite" themselves are a group of powerful metahumans who operate beyond the limits of the law, with Black leading the way. Menagerie, for her part, was bound to symbiotic parasitic alien lifeforms known as "symbeasts" through an experimental procedure conducted by a rogue section of the DEO known as the Men in Black (no, not those Men in Black). The character is thus able to create a variety of weapons using the "symbeasts" and use them to attack her opponents, as she deems fit.
While Menagerie's storyline will no doubt be changed for the show, one can already start to imagine how the villain/antihero might be adapted to the world of Supergirl. Seeing as Lena Luthor (Katie McGrath) is currently working on a procedure that would give regular humans alien-like superpowers, it's entirely possible that she will be the one responsible for granting Pamela her powers in the first place. Likewise, it stands to reason that when Manchester gets out of jail (which he definitely will in the latter half of season 4), he might join forces with Menagerie and similar "Elites" in order to continue battling Lockwood and the various Children of Liberty on his own terms.
Meraz's turn on Supergirl reunites her with WBTV (which also produced her TNT series Major Crimes) and is described as a "major recurring role" in Deadline's report. That further suggests that Menagerie won't be a one-and-done villain of the week and will (presumably) work alongside Manchester for several episodes to come. Likewise, there's a solid chance that even more members of the "Elite" - like Rampotatek aka. The Hat and Nathan Craig Jones aka. Coldcast - will be cast on Supergirl over the forthcoming weeks, as the show continues its mid-season hiatus.
Supergirl continues Tuesday, December 11 with "Elseworlds, Part 3" on The CW.