Season 11 - The Darkness\n\n While its ending may not be as impactful as others, season 11 is a pretty great post-Kripke season of Supernatural, and the Darkness, a.k.a Amara, is the main villain of that season.
Lucifer kills the rest of the band and beats Castiel and Crowley, though the Winchesters scare the rest of the humans away to safety. Lucifer reveals he has no plan and is upset that God apologized to him only to leave again to be with Amara.
