"That Light in the Window" from Madame Xanadu vol.2 #11 (Vertigo, 2009) by Matt Wagner and Mike Kaluta
Her name sounds ridiculous, but it's probably down to the Olivier Newton John rollerskate musical. She's immortal, something that today allows her to serve in both Demon Knights and Justice League Dark, centuries apart. Written by Matt Wagner, he didn't do the art, though it seems he was usually partnered with someone superlative. Mike Kaluta is one, Amy Reeder is another. I've only got a handful of issues. Maybe I should remedy that.