Organizing ideas for a story. Help me brainstorm?
I'm going a little outside my area of expertise and want to experiment with crime with a supernatural element.
I'm starting a story about a guy who helps a female cop solve murders, but he's also possessed by a demon. I'm still setting the story up, so my ideas are a little chaotic and I need help organizing what is good and what is too much. I just don't want so much "magic" that it becomes an Urban Fantasy.
I don't know if the word "demon" will ever be used, but it's a supernatural spirit that takes possession of him between midnight and 3am. This spirit heals him if he's injured. This part I want to keep.
Other ideas include:
The demon being a spirit of lust and anger, and gives him visions or dreams of when a nearby murder occurs.
Also, I don't know if the main character should remember the what happens when the spirit takes over.
Any other ideas are greatly appreciated.