Supernatural's Castiel will be far from pleased when he discovers Dean Winchester's new identity in season 10.

'Supernatural' 200th Episode Plot Revealed, Carver Edlund Books Resurface As Play

Castiel's (Misha Collins) best friend is now one of hell's most powerful demons, and the rebel angel will want this new monster out of the picture ASAP.

"It's definitely driving a very, very large wedge between the two of them," Collins told Zap2It. "I think that Castiel really doesn't see Demon Dean as Dean. He sees him as a monster that, one way or another, needs to go."

Demon Dean A 'Womanizing Party Animal', More Than Crowley Can Handle On 'Supernatural'

Busy quashing the last members of Metatron's army and dealing with his failing grace, contemplating potentially offing Dean (Jensen Ackles) will be just another worry on Cas' plate. In the meantime, viewers will get to see Cas take on a strong storyline of his own.

"The storylines are going to be interwoven, but there's also going to be a strong, independent storyline for Castiel in Season 10," Collins explained, adding that "It feels like we're dealing less with the massive, epic stories of heaven and hell and more with the personal stories of the characters that we've all come to know and love on the show."

Find out how Team Free Will fares when Supernatural returns to The CW on Oct. 7 at 9 p.m. ET. Click the video below to watch Cas take down Metatron and learn of Dean's death in the season 9 finale, "Do You Believe In Miracles."

Tags: supernatural television the cw