Yes, there might be such a fanfic. Fanfiction often explores unique and creative concepts, and the idea of a character like Belatrice Decker being Lucifer's daughter is an interesting one that could attract fanfic writers. They might use this concept to create all kinds of stories, perhaps exploring her powers, her relationship with Lucifer, or her role in a fictional universe.
Chloe Decker's dad doesn't die in the comics. The storylines don't include that event. Maybe there's some confusion with a different version or interpretation, but in the original comics, he remains alive throughout.
It could be a story of self - discovery. Belatrice might start to notice strange powers or abilities within herself and gradually realize her connection to Lucifer. She could then struggle with whether to embrace this part of her or try to reject it and be 'good'.
I don't have enough information to know exactly who Bobby Decker is in this story. He could be a child, a young man, or even an older person. Maybe he's a local character in a community where this Christmas story originated.
David Baldacci is a well - known author who has created this series. His writing style is engaging and he is great at creating suspenseful plots, which is evident in the Amos Decker novels. He has a talent for developing characters like Amos Decker that readers can really get invested in.