The villain is a part of Manchester Black’s evil squad The Elite on the page, and this is as sure a sign as any that Supergirl may be introducing the antiheroic comic book team.
Menagerie, first introduced in Action Comics in 2001, initially got brought into Manchester Black’s mission to rid the Earth of scum, including Superman.
She’s got a pretty particular talent, too, as she’s able to control symbiotic alien parasites.
Let’s get Vera Black and Coldcast added soon, shall we?