I'm sitting here and Underworld: Rise of the Lycans is playing on tv. I just happened to turn around when Sonja is standing there looking down at Lucien in his cell. And I think, wow.. it's Serana's twin!
Although, this could also be just that they both have dark hair and both have full lips.
Yeah, I know there are many things in Skyrim that are reminiscent of things from other movies and such. I just never placed this one until now.