Sam and Dean Winchester are back, and they will be waging their final battle against all the demons and supernatural forces they ever defeated. With so many evil souls lurking out freely, things are going to get intense. According to the spoilers for "Supernatural" season 15 episode 2, they will be calling out for extra help from old allies.

[Spoiler alert! This article is titled "Supernatural" season15 episode 2.]

The second episode of the final season of The CW series is titled "Raising Hell" and the two demon slayers will be calling on Rowena to help them in their final mission. Rowena, a powerful witch, has resurrected several times even after being killed by Lucifer, the Satan. So, there is no better ally to help the Winchester brothers in their fight. Sam and Dean ask her to help them in keeping all the dark forces at bay. At the same time, they find an unexpected friend and assist Ketch, a mercenary hunter who was formerly a member of the British Men of Letters.

Meanwhile, fans can expect a favourite character to return to the series. According to TV Guide, the very first special guest of the final season is the prophet, Lord Kevin Tran. He will make his first appearance in the final season in the upcoming segment to keep the world from falling prey to the dark forces.

Kevin, played by Osric Chau, made his first appearance in "Supernatural" season 7 titled "Reading is Fundamental" and proved his allegiance to Winchester brothers quickly. He translated the Angel tablet and was killed by Gadreel. In season 13, fans witnessed Kevin's avatar from an alternate universe. It remains to be seen whether season 15 will feature the real Kevin or his ghost.

The trailer for the second episode is expected to be out after the broadcast of the premiere episode "Back to the Future." Keep checking this space for more updates.

When Sam and Dean return this time, they are not only fighting the evil souls, but also God.

"When God is your uber-villain, it's not just a one-episode deal," executive producer Bob Singer told Variety. "It's not simple, just going for Chuck, and a big part of what we're dealing with in the season is how to do that. At a certain point, Chuck will be at full strength, which gives our boys even more problems," he added.

Supernatural season 11
Supernatural stars Misha Collins, Jensen Ackles and Jared Padalecki The CW

"Supernatural" season 15 stars Jared Padalecki as Sam, Jensen Ackles as Dean, Alexander Calvert as Jack, Misha Collins as Castiel, Ruth Connell as Rowena, David Haydn-jones as Ketch, and more.

"Supernatural" season 15 airs Thursday on The CW.