Supernatural's longevity is something of an ongoing joke for journalists. To the show's loyal fanbase, it's been a blessing. The CW series began airing in 2005 on the network's precursor, The WB, pre-empting the dawning of the post-Twilight "dark fantasy" craze that continues to grip media aimed at the young adult demographic.

The show follows brothers Sam and Dean Winchester, who were trained by their father to hunt the supernatural. Following their mother's mysterious death and their father's disappearance, Sam and Dean head out on the road looking for answers -- and the odd monster to kill.

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Even though comic book characters from DC and Archie have come to dominate its programming, the Winchester brothers' adventures have remained a flagship property for The CW. While its 14th season is still airing, the recent announcement of a 15th marked business as usual. Then, the moment fans had been dreading finally came: The additional announcement that the 15th season would also be the show's last, which of course means it'll be the most significant in Supernatural's run.  

THE BEGINNING OF THE END

Stars Jared Padalecki, Jensen Ackles and Misha Collins broke the news on social media in a watery-eyed video on March 22. "We wanted you to hear from us that, though we're excited about next year, it will be the finale -- the big, grand finale of an institution," Ackles said. "We've cried some tears and we'll cry some more," Padalecki added. "We'll work all the emotion into next season."

Executive producers and co-showrunners Robert Singer and Andrew Dabb, who have been part of the series' production since the show's first and fourth seasons, respectively, also released a statement thanking the cast, crew and network, as well as emphasizing their intent moving into Supernatural's final chapter. "It is now most important to us to give these characters that we love the send-off they deserve."

ALL THE MILESTONES

Sam and Dean have raised the dead, crossed dimensional thresholds and rubbed shoulders with the who's who of cosmic beings during their extraordinary lives. In our reality, Supernatural's life has been similarly impressive. After the show concludes with its 15th season, its total episode tally will reach 327, strengthening its title as the longest running sci-fi/fantasy series in the history of American broadcast television. It's also the longest running drama series The CW has ever produced.

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This is a particularly incredible feat for a genre series, which have a much shorter shelf lives without the cookie-cutter, open-ended storytelling that episodic hospital, crime and comedy shows usually employ to prolong their stay. Supernatural is currently competing with Criminal Minds as the joint 14th longest-running scripted American primetime television series of all time.

NEXT PAGE: How Supernatural's Leads Envision the Series Ending

SEASON 15: THE ROAD AHEAD

The 15th and final season of Supernatural is set to air in 2020. At 20 episodes, it'll be the show's second shortest after Season 6's 16-episode run (the original 22-episode order was reduced because of the Writers Guild of America strike.) As Season 15 is still in development infancy, little information is available yet as to what it will entail. It seems extremely unlikely that the main cast -- Sam, Dean, the angel Castiel, Lucifer's Nephilim son Jack and the resurrected Mary Winchester -- won't be returning to see things through to the end, though.

More likely is the appearance of some other familiar faces from the past. The 300th episode found a way to reunite the Winchester family with their long-dead dad, played by Jeffrey Dean Morgan, and old favorites like Bobby Singer, Gabriel and Charlie Bradbury have already made improbable returns. Top of every fan's list will undoubtedly be the former King of Hell, Crowley, who sacrificed himself to close an interdimensional rift in Season 13.

WHAT DOES THE END LOOK LIKE?

Had creator Eric Kripke's plan gone ahead, Supernatural's original ending would have been the season finale of Season 5, which saw Sam and his and Dean's half-brother Adam trapped in Hell with Lucifer, leaving Dean to move on with his life with his newly discovered son (the "apple pie" life, as Dean calls it.) Neither brother has ever expressed the belief that they think their lives will end this bloodlessly.

As of the time of writing, Season 14 has yet to finish airing. Given Lucifer remains the show's longest-running villain, his return to power in time to try and finish what he started would be fitting. But fans have also longed for Adam's return; a callback that would be on par with the Red Skull's cameo in Avengers: Infinity War by this point.

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Naturally, the subject of the series finale has been playing on the minds of the two main stars for some time. In 2017, Jared Padalecki told Entertainment Weekly that he felt like he "either want[s] the boys both to die or for Sam to die." Jensen Ackles, on the other hand, revealed in the same interview that he has a much more vivid imagination. Get ready to grab the tissues:

"I can see it now. It's just one scene. Think: Middle America, Big Sky country. It's just wheat fields as far as the eye can see, and there's an intersection, a crossroads, oddly enough. I drive up in the Impala, and I park in the middle of the intersection. There's nobody for miles. I get out of the car and I look in the distance -- and it's like Lawrence of Arabia when Omar Sharif was running up with the camel -- I just see a thing coming in the distance, and it gets closer and closer and closer.

"It's a guy on a motorbike. And we never really see his face. He's got a helmet on. But he walks up and I give him a nod, and I take a walk around the Impala very slowly and I walk back over to him and I hand the keys to him. And he takes off his helmet -- we don't see who it is -- he hands the helmet to me and hands me the keys to bike. From his back, he gets in the car and I watch the Impala drive off. And then I turn and I look at the bike that's got one seat. And I put the helmet on, start the bike, [give] one last look to the Impala, it's gone now, and I take off.

"Because I don't need the extra seat anymore. And I even have the soundtrack in my head. There were no words spoken. I had this swelling score. It was like some Robert Zemeckis film."

Airing Thursdays at 8 p.m. ET/PT on The CW, Supernatural stars Jensen Ackles, Jared Padalecki, Misha Collins and Alexander Calvert. The Season 14 finale airs on Thursday, April 25.