one hell of a butler (male demon needed)

The new black butler season dropped, and made me remember how much I love the concept of hot demon butler that’s amazing at everything. So I want to do a roleplay that follows a similar premise! 
 

though rather, instead of playing a young boy like ciel, I’ll be playing a young girl to be the demon’s young master/mistress, whatever you want to call her. So you have to be okay with the massive age gap to roleplay this!

The general plot is:

My character comes from a wealthy family. Like, scary wealthy. During a regular night, on a family outing ends in a planned attack that leads to my character’s parents to be killed, and herself beaten and planned to be sold. With no other option, she resorts to forming a contract with a demon, in exchange for her soul. 
 

The demon appears and kills the men, saving his new mistress and taking her back home where he tends to her, and protects her from an unknown agency that wants her dead now, in order to take the wealth that now falls under her name. 
 

The demon, skillful and deadly, can do almost anything. The only downside is his hunger, which he can only sate in the meantime by fucking his dear mistress,draining energy from her. He can’t have her soul until his duties are complete, so it’s a fair off trade, he’d say. 
 

The gist is pretty simple, and the plot mainly revolves around people from the unknown agency trying to kill my character, your character protecting her, and trying to find out this agency and who pulls the strings. Since it’s pretty to the point and simple, I don’t mind you including stuff to make the plot spicier, or if it’s kink stuff, because obviously sex is gonna be happening between our characters.

For your character, like I mentioned, he’s pretty much great and excels at everything, but please give him quirks! Living in the human world, there’s bound to be stuff that fascinates him, leading him to have things he likes/likes to do (basically like how sebastian is with cats, haha) 

Dont forget to check out my preferences, and as usual, please be competent and have lengthy replies. It doesn’t have to be novel length, and I don’t mind it being on the short side sometimes, but preferably I’d like replies with effort in them! Thanks for reading, and I hope to rp with you!