Darth Vader is arguably one of the most iconic film villains of all time. From his first moments in Star Wars: A New Hope, his role as an intimidating, and virtually unstoppable, threat is undeniable. He had complete command over the force, could wield a lightsaber with skill and always seemed to be four steps ahead of his enemies at every turn, despite initially being presented as just a lackey for Grand Moff Tarkin and the Emperor.
However, one fan theory suggests Darth Vader may have been less a threat to the Rebellion and more like its greatest asset. Proposed on Reddit, the premise is that Vader intentionally allowed the Rebels to escape with the Death Star plans, and his relationship with the Emperor supports that.
The bulk of theory's evidence comes from Rogue One: A Star Wars Story, in which Vader attempts to seize the plans, only for them to slip through his gloved fingers. The sequence presents Vader as a force of unstoppable power, yet, despite that, he takes the time to hack through each of the Rebels.
It's almost as if his assault is some sort of show of power rather than him actually trying to achieve his supposed aims. He could even be deliberately taking out his anger on a weaker target.
The theory goes on to argue that Vader had by this point realized how much wanton destruction the completed Death Star could inflict -- an unnecessary amount to achieve the Empire's aims. Though Vader serves the Emperor, his main motivation has always been to restore order and control to the Galaxy. So, while Vader makes a big show of retrieving the plans, he also avoids the obvious, more direct solutions to thwarting the Rebels. Solutions like simply Force pulling the plans into his hand.
We see Vader for mere minutes in Rogue One, but it is clear from this small amount of time that he's no fan of the Death Star or the people in control over it. Tarkin? Different story. He is involved with much of the process, even exploiting circumstances to gain power over the planet destroying machine. Here, Tarkin is placed in a position of power over Vader.
Could Vader have also exploited circumstances to gain command over Tarkin? Or perhaps he felt that the Death Star's excessive power was the wrong method with which to establish order. After all, he does say, "Don't be too proud of this technological terror you've constructed. The ability to destroy a planet is insignificant next to the power of the Force."
Furthermore, Vader flies outside of the Death Star in the climax of A New Hope. He survives while Tarkin dies. Could this too be part of his plan all along?
When taking Marvel comics' Star Wars stories into account this theory becomes even more interesting. Vader is often at odds with the Emperor in the comics. It shows that Vader, while aligning with the Empire, often feels the Emperor's goals run counter to his. Especially when Vader becomes aware that the Emperor has manipulated him by hiding the existence of his children. While Vader is still unaware of this detail in Rogue One, he is already feeling disenchanted with the Emperor.
In fact, it seems at times that Vader is overtly plotting against the Emperor. In Empire Strikes Back, Vader suggests to Luke that the two of them could overthrow the Emperor and rule the Galaxy together. So, Vader clearly has ambitions of his own.
Could allowing the Death Star plans to slip through his fingers be part of a larger scheme concocted by a dissenting pupil?
While this theory is fairly convincing, it doesn't Vader's actions during A New Hope into account. Vader kidnaps and tortures Princess Leia, pursuing her across the Galaxy. His rage towards her seems raw when he believes she's lied to him about the nature of her mission.
Vader is many things. He can be manipulative. He can be a schemer. But, this fan theory ingored the fact that, during the other films, Vader never acts in opposition to the Empire. Not until his redemption at the very end. He believes the Rebellion is causing disorder. He sees the Rebels as the only obstacle in restoring peace. Ultimately, he believes that what he and the Empire are doing is for the "greater good."
There's no way he would aid the Rebellion he hates so deeply in any form. Plus, if he truly wanted to destroy the Death Star, he would have done it himself.