Um, hello I thought I would throw this idea up since the public version of it always dies for me....sadly.
See the story is that one day a girl got into a horrible accident and was on the verge of death. While lying on the ground she saw a figure through her blurred vision, but couldn't exactly see who it was but all she could say in a hoarse tone was "help". When her eyes shut she thought she was as good as dead, at least that's what she thought, but again her eyes opened and she was home in bed just fine, like the accident didn't even happen aside from all the bandages and stitches she had received. She could have sworn she was dead, she could feel her life just slipping away, but somehow she was alive and well.
The reason being was that a demon has given her his own heart to continue living, he did not know the reason why, but he did. How is he still alive without one you ask? Well as long as the girl remained alive so did he, but the thing is he felt her emotions, they were connected to one another. Sooner or later the demon will decide to take his heart back, being sick of feeling such things, but all in due time.
I know the story isn't all that great, but it's something I've had in my head for a while. I would like to play the role of the girl in this story and would like to find a female opposite to play the demon. I do mature content or not, it depends on my partner I don't mind time skipping and all that. I know it's not all that great....Gomen.