Alastor in Twilight AU:
Suggestions based on your idea of the book itself trying to keep Alastor:
Maybe in this AU, Lucifer started interacting with the other Sins again, and Mammon showed off a new spell he was working on- to make money, of course. And he asked Lucifer if he and Charlie would like to test it out before he puts it on the market? He was not expecting the panicked phone call literally the next day about how Lucifer 'fucked up, Charlie is panicking, he's panicking and now can't get Bambi out! HELP!'
On why the Twilight Saga, in particular: either Mammon used the Twilight books as a test run, because Charlie used to be is a fan of the series and being the Best Uncle, wanted her to have fun and 2) they were selling like crazy so surely they're a good choice to test out the spell on. Or maybe, Lucifer was the one who chose the Twilight series because he remembered it as a cheesy romance for teen girls that Char-Char used to like and thought it was the perfect opportunity to prank Alastor while also keeping him out of the way.
Everyone here seems to agree that Charlie is a former Twilight superfan, so what if we leaned into that and the book(s) themselves once belonged to her. Similarly to the Darkners in Deltarune, the spell gave the book series sentience and a personality forged from memories based on It's experiences, perhaps abandonment issues being stuck on the bookshelf collecting dust after being tween Charlie's favourite book. Maybe one of the reasons It latches onto Alastor is because It senses that deep down, he is feeling similarly abandoned by the Hazbins- Charlie involvement causing an even deeper connection- after the Last Extermination.
Adding onto the last bullet point, maybe the book creates Itself an in-universe avator for when It decides to get directly involved in the story. For extra points, It's avatar is based on Bella whose own design seems to be an idealised version of Stephanie Meyer herself.
What if to keep Alastor from leaving, the magic of the book starts to slowly and carefully erase the memories of his life from before? Imagine the horror he would feel when he realises he can't remember the names faces of the ones he trying to get back to but he is certain that they existed.
Something for him and Alice to bond over, writing scrapbooks of their memories! Alastor's memory scrapbook has doodles of people with incomplete faces and notes beside them, perhaps like Jacob's letter in Eclipse the book shows it, almost like a taunt.
Accurately drawn Charlie except for the blank face doodle: She was pale with rosy cheeks. Falsely cheerful, kind but cruel. She likes rainbows and glitter too much. She loves to sing. I think her name sounded like dad's. Just thinking of her makes my chest ache. It hurts. Vaggi with an exaggerated scowl doodle: She was small and angry with long pale hair. I think she was a soldier of some kind. She hated me. Angel Dust, missing two arms, holding a phone: Tall, fluffy and vulgar. He made me uncomfortable. Pitiable. Untrustworthy. Avoid him. 'You can't help someone who won't help themselves.' Extra scruffy Husk doodle: CAT? Grumpy. Stinks of booze and shame. Likes the tall fluffy one. I hope he hasn't *unintelligible scribbles* Adorable Niffty holding a tiny knife doodle: My favourite. Tiny but mighty. Likes bugs and sharp objects. She was the only one who *scribbles* I miss her. I wonder if she also- Sir Pentious' top half surrounded by egg-shaped figures doodle: Looking at this one makes me feel... sad? Angry? Ashamed? Responsible? I can't remember why. Confusing. I remember he used to make me laugh. Lucifer with a red eyes and a sharp smile doodle: I had grossly underestimated his sadism. I still remember how he had smiled before sending me here. My memories and sense of self are melting away even as I try desperately to grasp them. This was his plan all along. I hate him I hate him I hate him I hate him- Headless Vox doodle: Liar. Stalker. Vaguely feminine shaped doodle: You were the only one to ever love me unconditionally. I didn't want to forget you. I'm sorry that I can no longer remember your face. I'm sorry that I can no longer remember your voice. I'm so, so sorry. Forgive me, maman.
Duckie, Now you have given me some food. But the way I was going with the magic was like this. It is creating a world where Alastor is listened to, he is cared for, and others don't look at him and only see what he can do. They are more than willing to pull their own weight, otherwise? Vampire covens would collapse. So the magic takes that and shows Alastor. See, they are helping, they aren't just leaving everything for you to deal with. They are carrying their own share of the burden as well. Alastor, who has been doing the vast majority of the work, wouldn't be used to it, and that is what the magic will use; it won't need to alter his memories to get Alastor to stay. All it needs to do is simply prove that everything is better here, and all Alastor needs to do? Is stay. That is it. It isn't asking for Alastor to carry the majority of the work, there aren't others that are mocking him because he is a Sinner, there is no one mocking him becuase of his dislike of modern tech, there is no one making lewd jokes that make him uncomfortable and no one seems to think that his comfort is something that needs to be considered. To those in the hotel, Alastor is a tool and a weapon. The magic is showing Alastor how much better his life will be if he leaves the hotel. See Alastor, a coven works together; no one vampire is expected to carry the weight of the coven by themselves. Charlie has taken an interest in your hobbies. When was the last time that someone other than Maman did that? Those in the hotel are going to see all of this; they are going to hear Alastor's thoughts about how strange it was to actually have help and not be ridiculed. To have someone stand by his side and not hide behind him as he dealt with yet another problem. So it won't need to erase his memories or alter them, not when Alastor's memories of what his life was like in the hotel are something that the magic can use to convince Alastor to stay. When was the last time you had someone listen to you and not disregard what you had to say? The worst part it? It is working, and those in the hotel can see that.
