The long-running dark fantasy series "Supernatural" is coming to end. The CW series that premiered more than a decade ago will bid goodbye to its long-time fans with season 15.

The 15th and the final season will see Winchester brothers take one last mission to save the Earth from the havoc of devils, ghosts, monsters and other supernatural beings. Recently, the network released a trailer for the upcoming season teasing the end of the series.

As per Fansided, the end of the series will be nostalgic for long-time fans of "Supernaturals". The latest trailer hints at the return of some of their old enemies and dark forces such as The Woman in White, the first-ever dark force they fought in the pilot episode in 2005. To make matters more challenging, every entity that they have defeated and put back in hell, is back.

The trailer opens with Sam (Jared Padalecki) revealing that it is the end. If they complete their one last battle, the brothers are free from their hunter duties. Nevertheless, there is nothing that Sam and Dean find unconquerable. "You and me versus every soul in hell. I like those odds," tells Dean (Jensen Ackles) to his brother in the trailer.

The boys have a lot of work to do before the final chapter comes to an end. Meanwhile, fans can expect a lot of old memories rushing back, as Winchesters fight the souls from early seasons.

Apart from every soul in hell, the leading men are going to face the wrath of God. After making Chuck angry, the brothers led him to open gates of hell and let out every force the brothers ever defeated.

Speaking to Entertainment Weekly, Supernatural star Jensen Ackles who plays the role of Dean revealed what's to come next in the final season. "We start right back up in season 15, and it is a bit of a triage situation. They gotta get out of there, they gotta find some shelter, and they gotta figure out what to do," he said.

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

He revealed that Supernatural Season 15 sees them up against God himself.

"This is, as far as we know, the most powerful being in the universe, and he's against us," Misha Collins (Castiel) said. The hunter brothers will continue to be surrounded and protected by their angel friend Castiel.

Supernatural Season 15 premieres on Sunday, October 20 on The CW.