The Prince of Hell (слэш)

He squeezed his eyes shut. What had just happened? Sam had completed the cure, he should be human again… unless he couldn’t be cured.
The cure has failed. Dean Winchester is a demon, and there's no changing that. But maybe some things can be changed. After all, Dean feels... different, after his brother pumped all that blood into him. It's not like how Crowley was after his almost-cure; Dean actually almost feels almost like himself again. So, what does a Winchester do when he realizes he's a demon and there's no way out? Take a seat on the throne of Hell, apparently.