(or "Mum," as Lucifer would say, and about whom they have yet to clear up just how she does or doesn't tie into any particular recognizable real-world faith/cosmology),
So, this season started tonight, and Mom is part of the cast, and she's played by Tricia Helfer. She only makes her first appearance at the end of the episode,
It's such a terrible show, but the cast is so great. Also, they're not above making great big obvious nerd jokes like this one, and I find I just can't be mad at that.
Don't get me wrong, I'm constantly disappointed that it's basically Castle with The Devil and not an actual adaptation of the comic series, whose Lucifer is very much not this. But, still, yeah.