O criador Eric Kripke confirmou que Dean Winchester  esta vivo e tb disse que ja tinha planos para a proxima temporada para os irmãos.

Jensen Ackles, Supernatural

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TVGuide.com: You weren't lying when you said you were hoping to make your fans really angry and full of anxiety all summer!
Eric Kripke: [Laughs] It was a fun way to end the season. Dean meat-hooked in the center of what looks like a thousand mile spiderweb of rusty chains. Sort of M.C.Escher meets Hellraiser.

TVGuide.com: Why did you send Dean to hell?
Kripke:  Everyone expected Dean to be safe! That's reason enough to send him to hell. But also, in ways I can't reveal, it's a turning point for Dean. You need huge moves to happen that can cause radical shifts in the characters, that set them off in a new direction. So what happens to Dean in hell and how Dean gets out become primary concerns of Season 4.

credito : www.tvguide.com