(Castiel kills Billie…)
Castiel (to Sam and Dean): You know this world, this sad, doomed little world, it needs you. It needs every last Winchester it can get, and I will not let you die. I won’t let any of you die. And I won’t let you sacrifice yourselves. You mean too much to me, to everything. Yeah, you made a deal. You made a stupid deal, and I broke it. You’re welcome.
From Supernatural – Season 12 Episode 9: ‘First Blood’ (12×09) | TV series produced by The CW