Nifty is Eve in disguise
This theory adds onto to a few other popular ones, that being Eve is Alastor's dealmaker under the guise of Lilith, and Eve is the cryptic "Roo." What I propose alongside that, is that she's hiding in plain sight among the hotel guests, and that disguise is Nifty.
Spoilers up to the season 1 finale below:
Evidence:
When you think about her in conjunction with the show's established themes it falls into place: Adam, the s1 antagonist is a misogynist who wanted Lilith's obedience. Eve will foil Lilith; while she's all about hating subservience and breaking chains, Nifty is a parody of the stereotypical 50s housewife, 'likes being forced' and spends her time cooking, cleaning, and obsessing over men. Eve was created from Adam's rib to ensure his next wife would lack the autonomy to rebel. Designed to be the epitome of Adam's submissive ideal, it makes sense Eve would choose a 50s housewife as her disguise, they resonate with her.
The old logo is her face / her and Lucifer's placement on the prime cover.
She collects little pieces of men because that's what she was made from / is enamoured with Pentious in particular because he's a snake. "never leave me again" <- double meaning alert. / "HATED THAT SONG" because she was never offered forgiveness so easily. Not even Charlie catching her in the trust fall is foreshadowing; unlike Lilith who had Lucifer, no one came to her side when she committed the original sin.
The all-female exorcists were made by Adam to serve him. Their masks have horns like Lilith and a missing eye like a cyclops. They're hybrid clones of the two wives that left him. Eve is the only character in the intro whose eyes we haven't seen.
Every large ensemble show has a mole arc and she's the only one with no established goals. It's always the one-note gag characters you should look out for.
There's no confirmation if Nifty made a deal with Alastor. I think Eve is the one who's got him 'on a leash' though he thinks it's Lilith. He lets Nifty follow him around and she plays up the fangirl persona to keep a close eye on him.
It's the perfect refuge in audacity disguise. Acting innocent in hell in suspect. Being an unhinged stalker raises no questions. Alastor himself says he has no idea what tf her deal is.
I made this theory a few days ago but I was delighted to see more evidence in the final episode. See this?
It's elaborate foreshadowing disguised as a gag. She's not just doing this for the funsies she is MAD mad. Vengeance!
Conclusion:
Whether this means she's the big bad or unlikely ally, I can't say. If it's the former, her goal is to be redeemed with the other guests and enter heaven so she can get revenge on everyone else. S1 leans heavily into heaven vs hell so it would make sense for the final antag to be a 3rd party wildcard who wants to burn both sides to the ground for failing her. Heaven casted her out, hell unintentionally doomed her to an eternity of suffering with the fruit of knowledge, then left her.
Nifty be Shifty.
