It will be a Dark Fantasy. There will be some tragedy due to demons not caring about who they make contracts with and there might be multiple demons in one world.Something that always confuses me is when people don't explicitly mention the genre they want their story to be.
Like, it's clearly a fantasy, but is it meant to be a dark comedy? A tragedy? Because that will very much change the feel of the story, and might make certain worldbuilding ideas more preferable than others.