Eric Kripke parle de la prochaine saison

Eric Kirpe reveals: What happens to Dean in hell and how Dean gets out become primary concerns of Season 4. [...] Dean spends a lot more time in hell than anyone's probably thinking. Dean could spend - in human time - six months, maybe more. In hell time, who knows how many years or decades that might be. I won't tell you how he gets out, but he will emerge to a different landscape. A lot has changed since he's been away, and he has to readjust to his loved ones after being gone for so long. [...] It takes hundreds of years to be burned away into a demon. Dean won't be a demon, but there will be an ongoing mystery. When he gets out of hell, he'll have little recollection of what happened to him down there. That's one of the mysteries of the season. [...] Ruby will be back, and we're introducing a new supernatural species. We intend to bring back Steve Williams, the old embittered hermit hunter Rufus. [... Dean's hellish sojourn] will affect [the relationship between the brothers] massively. We'll slowly unfold Dean remembering what happened in hell, and that will drastically affect their relationship. Dean is basically a POW coming home from the worst hellhole - literally - ever. How do you reconnect with your life when you've been through something that horrific? That becomes one of his issues. But don't worry, he's still the same smart ass he always was. [...] We presented [Sam] as immune to [demon Lilith's] powers. We have some twists and turns in store with that. Sam promised Dean right before Dean died that he wasn't going to pursue any of his powers in terms of discovering his potential. Upon Dean's return, Sam tells him "I promised I wouldn't head down that road because you made me promise," but we begin to wonder if indeed that is the truth. For whatever it's worth, the writers have never been this excited about a season. We have some really exciting plot twists.

Source: TV Guide Online