Supergirl has had a few major archnemeses but some might argue that none surpass the Silver Banshee. In the most recent comic reboot of the character, Siobhan Mcdougal (Silver Banchee), actually was Kara's first friend. They did have a rocky fight earlier but their friendship does seem intact still. So as more and more information is leaked about CBS's new show, speculation on who will be the Lex Luther to Supergirl abounds.
We have already learned that CBS and Supergirl scribe, Greg Berlanti and Ali Adler are mixing and matching previous cannon with Kara's orgins. We know she is adopted by the Daverns family at the age of 12, which is a bit different than previous iterations. Also, if Arrow is any indication, previous comic-book lore is loosely adhered to. Looking at Black Canary on Arrow gives a lot into what show creators are willing to do with the DC characters. So when it comes to the Silver Banchee, its anyone's guess if she'll be friend or foe, or even on the show.
In other villain speculation, it can't go unnoticed that Kara's foster sister's name is Alex ... Alexander ... Lex?
