One of the wildest theories surrounding Joss Whedon's beloved TV show, Buffy the Vampire Slayer, proposes that the events of season 7 caused a ripple effect—known as the "Universal Slayer Theory"—that trickled into other major existing Whedonverse properties.

If the theory holds, it would connect not only Buffy and its spin-off series, Angel, in a different way than the many other crossovers that have aired between the shows, but include FireflyDollhouse, and his horror-comedy movie with Drew Goddard (Cloverfield), The Cabin in the Woods. Similarly, other spin-offs of the Universal Slayer Theory have purported that literally every show and movie by Whedon can be connected somehow. Buffy the Vampire Slayer was arguably some of Whedon's finest work, and launched the director and writer into the household name he has become. Based off the 1992 movie of the same name, Buffy the Vampire Slayer released on The WB in 1997 and saw success with seven seasons—though eventually switched networks to UPN—until its series finale in 2003.

Related: Angel: The ONE Thing The Spin-Off Did Better Than Buffy

Other Whedonverse shows, such as Fireflywhich only got one season—and Dollhouse weren't as successful, but remained no less popular amongst their respective, highly devoted fanbases. Angel, the spin-off show to Buffy the Vampire Slayer which put the Slayer's vampire boyfriend in the leading role, was canceled after season 5 in 2004. While Buffy the Vampire Slayer and Angel were the only shows to directly reference vampire slayers and their distinct heritage, the theory suggests that the Buffyverse is but a microcosm, and Slayers exist far and wide in the greater universe.

Buffy's Series Finale Opened Up The Slayer Line

The Slayer line was shaken up through Willow's (Alyson Hannigan) magic in season 7, to grant the powers to any and all young women who have the "potential" to be called as a Slayer in full. Prior to this, there was only one active Slayer at any given time, and the next would be called upon her predecessor's death. Willow unlocked the magical powers of the Scythe, which Buffy used to kill one of the Big Bads of season 7, Caleb (Nathan Fillion) before placing it in her friend's highly-capable hands. Though Willow was concerned that tapping into such intense magic might cause her to revert to Dark Willow, she ended up being the linchpin of Buffy's final battle against The First Evil alongside Spike, who heroically sacrificed himself to take out both the Hellmouth and a swarm of Turok-Han vampires.

The Universal Slayer theory suggests that this distribution of power–which was always meant to only belong to one young woman—was the first part of a series of chain events, which was continued in Angel, that angered the mysterious and powerful Senior Partners. Some elements of the Slayer's powers are purposefully mysterious; the first Slayer, Sineya, was a young woman who literally got chained to the earth by her people and forced to fight demons. It's likely that the origin of the Slayer's powers is part of a universal series of checks and balances. This concept is greater explored through several aspects of Angel, such as Angel and Buffy being unable to be together after Angel becomes temporarily mortal in season 1, episode 8, "I Will Remember You". Angel turns back time and sacrifices his happiness with Buffy after talking to The Fates, who imply that he is no longer in service to The Powers That Be and could endanger Buffy as a result.

Angel Season 5 Triggered The Events Of Cabin In The Woods

One of the major villains throughout Angel is the demonic law firm Wolfram & Hart. It is through this organization that the Senior Partners are first mentioned, though always in a relatively ambiguous capacity. In season 5, Angel and his associates fight to take down the Circle of the Black Thorn; according to the theory, it is this action that awakens and angers the Senior Partners, who have been appeased by Wolfram & Hart's agents for quite some time. It continues by suggesting that the Senior Partners being dormant could be a key factor in preventing an apocalypse that would completely decimate mankind and the world. Therefore, it's in humanity's best interest to work with keeping them happy.

Related: Why Joss Whedon's Angel Was Cancelled After Season 5

This is potentially where The Cabin in the Woods comes into play. The theory connects it to The Initiative, a secret military organization introduced in Buffy the Vampire Slayer season 4. While much of what The Initiative does is seen to be experimenting on "hostiles"—various demons and monsters—and microchipping them in order to keep them from becoming more of a problem to society, it's possible that they are behind the sacrifices shown in The Cabin in the Woods. The Initiative was always a very high-tech, secret organization, and there's nothing that would imply they are strictly connected to the US Government; The Cabin in the Woods suggests that the trials that pit human sacrifices against various supernatural threats in order to test their worthiness and mettle are executed globally. The Ancient Ones, as they're called in The Cabin in the Woods, could be the Senior Partners.

The Director (Sigourney Weaver) explains that these rituals are conducted in order to ensure the apocalypse doesn't happen; the theory suggests this practice was adopted by The Initiative after Angel season 5. The Cabin in the Woods ends with the Ancient Ones/Senior Partners rising to destroy humanity after Dana refuses to sacrifice the virgin, Marty, which—according to The Director's rules, which are straight out of slasher movie tropes—must be done in order for the ritual to be complete. While the world presented in BuffyAngel, and The Cabin in the Woods may have been destroyed, the theory continues with Whedon's futuristic sci-fi series, Firefly and its movie continuation, Serenity.

Buffy & Firefly Connection: River Tam Is A Slayer

River Tam pointing at someone in Firefly

Firefly takes place in 2517, over 500 years after the events of Buffy the Vampire SlayerAngel, and The Cabin in the Woods. River Tam (Summer Glau) is said to be an exceptional young woman, and because of this, is experimented on by The Alliance. When River Tam and her brother, Simon (Sean Maher), board Serenity, a ship run by smugglers who oppose The Alliance—aka "Browncoats"—some of her abilities are seen, but her true powers are showcased in the movie Serenity (2005). The theory suggests that The Alliance was formed by surviving members of The Initiative after the events of The Cabin in the Woods, but the timeline gets a bit murky.

According to Firefly canon, the Earth became slowly inhabitable for humans due to global warming and other contributing factors that seem more natural and less supernatural. By 2030, which would be approximately twenty years after The Cabin in the Woods, the Earth was said to be completely unable to sustain human life within the next century. This would mean the Senior Partners/Ancient Ones didn't decimate the planet immediately, but contributed to global collapse over time. Even so, the rest of the theory, which suggests River Tam is the first Slayer to appear in roughly 500 years, makes sense given her abilities, general age, and the fact that she was deemed especially rare and interesting by The Alliance.

Related: Firefly: What Happened To Mal After Serenity (In Canon)

The theory also suggests that River's "treatments" and experimentation was done by The Alliance to trigger her Slayer powers, possibly so they could learn how to reclaim Earth from the Ancient Ones or whatever demonic presence is there. This also contradicts the more natural collapse of the planet that was discussed in Firefly, but isn't outside of the realm of possibility.

Dollhouse Could Connect To The Whedonverse—Here's How

Dollhouse ran on FOX for two seasons and starred Buffy the Vampire Slayer alum, Eliza Dushku, as Echo/Caroline. Echo is part of a program that uses humans who have been programmed to become blank slates to fulfill different roles for clients, based on their specific needs. While not directly linked to the theory, some have suggested that Dollhouse could link into the greater Buffyverse/Whedonverse through Wolfram & Hart. The facility could be operated either by them directly or some other affiliate, and some of the "personalities" that are imprinted onto the Actives could be linked to Slayers. It's also possible that Caroline was a Slayer before she was wiped clean.

If Dollhouse was part of the larger Universal Slayer Theory, it would probably fit in somewhere between Angel season 5 and the events of The Cabin in the Woods, though episodes did explore some sort of post-apocalyptic future; this could be the aftermath of The Cabin in the Woods or even more directly after Angel's series finale. The Dollhouse, run by the Rossum Corporation, had a branch in Los Angeles, the setting for Angel. Even if there are some major holes with the overall timeline that this theory rests on, specifically with when and how the Ancient Ones brought about the apocalypse and pivoted into the events of Firefly, it's fascinating to think the events of Buffy the Vampire Slayer could have continued into so many other Joss Whedon shows.

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