'Supernatural' Season 12 Finale Spoilers: Winchesters' Allies Will Die For Sam, Dean; Cas Makes Return In War Against Men Of Letters

"Supernatural" is no stranger to killing off characters, major or minor. Even Sam and Dean Winchester have spent their own fair share of time in Hell and Purgatory, coming back to life and putting themselves in danger anew as they battle the Monsters that threaten the earth. For the "Supernatural" Season 12 finale, showrunner Andrew Dabb warns that not all the characters may make it out alive.

According to Dabb's interview with TVLine, the "Supernatural" Season 12 finale will be set in the aftermath of Mick's death with the British Men of Letters out for blood and wanting to kill everybody. For the first time, in order to save the hunters, Sam and Dean would need to step out of their comfort zone as soldiers and lead the hunters to survival against the organized attacks of the British organization.

Dabb said that the "Supernatural" Season 12 finale will see the return of Cas who spent a lot of time with Heaven and this will clear out any confusion of viewers who felt like he abandoned the Winchesters in their time of need. Dabb said that Cas will make everyone understand the importance of the Winchesters in the grand scheme of things and establish his loyalty to his adopted family.

"Whether it's Cas or Crowley or Mary or Mick until his unfortunate demise or anyone else in our story, these are people who realize Sam and Dean's importance," Dabb explained about "Supernatural" Season 12's finale. "Sam and Dean have always been willing to sacrifice for each other. Now we're seeing a lot of people around them that are willing to sacrifice for Sam and Dean, and it's really about building a sense of community."

According to TV.com, "Supernatural" Season 12 finale will air on May 18, 2017, on The CW. There are still three episodes left before the season finale.