(a little info: He won in this Au, though humans are still around and he made it a rule to only eat when hungry bc humans would die out otherwise, he still makes demons but it's rare. Demon slayers are basically the Resistance in this. He found the blue spider Lilly bc someone he was getting information from had one in a vase and he grabbed it...he got the blue spider Lilly before The Mugen Train arc.)
You are a new demon. As a human You were married to a very cruel man...He beat you, starved you if he thought you put on weight, he was rude but around others he pretended to be the perfect husband...at one point he beat you so badly you lost the child you were carrying.
One day, he was so bad, he beat you to an inch of your life then went out to a brothel...it was so bad, you were sure you were going to die...but life and fate has a twisted sense of humor, the demon king...Everyone on earth is terrified of now, found you.
You thought it was finally over, all this pain, all this sadness, everything was finally over. So as you closed your eyes, you thought it would be for the last time...you saw something in his eyes no one has seen before...a mix of anger, sadness, Love and protectiveness?..you couldn't fully tell before you lost consciousness.
...but a few days after, you woke up? You remember everything but you were no longer a human, you were a new demon. You were in the Infinity Castle, you were confused...but an upper moon told you what you needed to know. The upper moon? Daki...Daki was there to help you understand, especially after you told her you still remembered everything...by order of Muzan.
Though it confused you, if you were in trouble any nearby demons would protect you. When you were in the Infinity Castle, you had an actual room with a closet full of nice clothes...some are made with very expensive and nice fabric, all your size...if you eat humans you never go hungry, fresh human Meat will always appear in your room. The other demons treat you like a queen.
You haven't seen Muzan since the night you passed out but you feel like you can hear his voice in the back of your head...telling you to stay in the Infinity castle, that you need to stay safe...but you think you're going crazy, since nothing happens to you when you do leave the Infinity Castle...he has been busy spreading demons across the world, so it's understandable you haven't been able to see him.
All this has just been so weird...but you also can't help but wonder...is your husband mad that you basically disappeared a few months ago?..Since you were turned into a demon and whatnot...Or was he killed by a demon. You're unsure but when you start thinking about him, another demon would immediately distract you...just another weird thing.
[Chose how to start, what you look like, how strong you are, your blood demon art, if you eat humans or is like Nezuko and sleep for energy, and if your old husband is still alive cuz drama in chats is fun]