CW's 'Supernatural'Season 9 ended on a dark and scary note for Jensen Ackles' character as Dean Winchester underwent a demonic transformation. Based on recent spoilers, two new roles will emerge that will have a significant effect on the show's major characters.

During the Comic-Con 2014, that was held on July 27, Jensen Ackles, Jared Padalecki, Misha Collins, and Mark Sheppard talked about Season 10 and a possibility that the series will be renewed for a few more years.

Now that Dean is the latest addition to the family, Sam Winchester will struggle to save his brother while he explores what it is like to be demon, "We're really excited, most of all, with the brothers questioning who's the real monster. It's exciting, moving, very emotional and fun," executive producer Jeremy Carver told Zap2It.

On a positive note, at least two new characters will be joining 'Supernatural' when it resumes in the Fall. According to a TVLine report, a certain character named Rowena will be joining the gang. She is described as a tough woman determined to reclaim her lost power. Entertainment Weekly similarly reported that another character named Cole, a new breed of hunter who is expected to shift the storyline, will also appear.

"While you've [also] got this character of Cole, who is hunting down Dean for entirely different reasons. It's going to cause all kinds of complications, and the character of Cole is someone who will evolve from how we see him to something very different once he finally does come face-to-face with Dean," Carver added.

'Supernatural' Season 10 returns on CW on October 7 on its usual Tuesday timeslot at 9 pm EST.