OKAY! That dynamic almost writes itself, really. Having Charlie fall from Heaven doing something morally ambiguous or wrong for the right reasons, maybe falling in love with a mortal and breaking the impartiality of Heaven to save them from their own sin for a classical example, then having Vaggie take her on as as an assistant or some other menial position within eyeshot after taking one look at Charlie and concluding, “This girl is going to get eaten alive.”
Vaggie’s reason for this could be from a place of pity, leveraging the situation as a way to piss of Lucifer because I don’t see how a child of Lucifer wouldn’t have daddy issues, or perhaps because having a Fallen Angel in your back pocket whose loyalty is completely secured by just being somewhat nice to her (something rare in Hell) is a smoking deal. A combination of all three? Maybe. Or many, many other possibilities.
The two wouldn’t even necessarily need to be in or get into a relationship with each other: Vaggie progressing from boss to mentor and then best friend as she helps Charlie navigate suddenly having full autonomy and grappling with vices without a divine ability to ignore temptation would organically generate comedy and tragedy in equal measure. Meanwhile Charlie would inspire Vaggie to have an open hand for her allies in the main cast and to reserve the closed fist for enemies because being pleasant isn't the same as being naive, something, something, Machiavelli quote goes here. A romance could form from that or it could stay a close friendship and it would still work.
Rework the hotel concept to be the upscale cream of the crop hotel for demon nobility (and angel emissaries) visiting Lucifer at the capital of Hell, which Vaggie was put in charge of as Princess of Hell and wherein the rest of the main cast works as guards or staff, then you’ve got the setting for the story with a literal revolving door of side characters to generate scenarios. So many characters work in this setup. Angel, Husk, and maybe Charlie later on as the mafioso type guards answering directly to Vaggie, Nifty being one of the maids, Alastor as the head of staff, and then Vaggie as the hostess running the show.
A dash here of showing how unfair and absolutely vile a realm where abuse of literally every kind is socially accepted so long as you have power, pepper some little shreds of redemption in how the main cast treats and interact with each other there (except Alastor who would serve as the sick bastard who likes it in hell), and then tie it all together with an undercurrent background theme of praying for a redemption you cannot and will never know how close or far you’re from embodied in Charlie’s struggles to fit in and survive while the blood soaked intrigue of Vaggie quite literally carving her place into demon high society takes up the foreground.
Voila. Narrative harmony between characters, plot, and setting.
