Title: Ballad for the Boy King
Authors: badbastion & thursdaysisters
Genre: casefic
Rating: PG-13
Pairings: Sam/Dean pre-slash, Sam/Lucifer if you squint
Spoilers: None. Set vaguely in S5
Warnings/Content: Mostly Gen, boyking!Sam, cursed!Dean, angst, Hell, h/c, possession, brotherly love, shifting POV. About 17k words.
Summary: Dean is cursed by Michael, and the brothers must travel to Hell while trapped in a tower of eternal darkness. All ways are open to the Boyking. Brotherly angst, blood magic, and boyking shenanigans ensue.

Read it on AO3 :)