It seems like there's a seriously rocky road ahead of Sam Winchester as he will need to exhaust all efforts in his attempt to cure his demon brother Dean. The tenth season of 'Supernatural' will showcase Sam and Castiel searching for a way to remove the Mark of Cain. However, executive producer Jeremy Carver explained why that's going to be more complicated than expected.

"First, there is no demon possessing Dean. It was his own soul gone twisted. Moreover, the Mark of Cain served as a puzzle that needed to be solved. There are some added dimensions in terms of levels of difficulty," Carver told Entertainment Weekly.

Additionally, Season 10 will introduce a new character to the series, one by the name of Cole. Carver said that Cole will add some twists and spins on the 'Supernatural' story. On a side note, previous spoilers revealed that Cole was once a part of Dean's past.

"He's a guy that has a terrific amount of hunting skills, but he's not a hunter in our sense of the word. He has no idea that the monster world exists, so imagine his surprise when he comes across the man he's been hunting and he is something other than human. He's a pretty cool character," Carver said about the addition.

The show's executive producer added that Dean's demonic transformation originated from the mythological part of the series, and that his cure will not be a total cleanse. Moreover, British actor Mark Sheppard has recently been promoted to a series regular in the CW paranormal drama. Sheppard, age 50, plays the role of demon Crowley.

'Supernatural' Season 10 returns to CW on October 7 at 9 PM.