Warning: contains spoilers for Eternals #6!
The Mad Titan Thanos and the Sith Lord Darth Vader are two of the most imposing villains in pop culture, and Marvel comics starring the pair confirm that when they face their heroic enemies, both subscribe to the same philosophy of battle. In Star Wars: Vader Down (Jason Aaron, Kieron Gillen, Salvador Larroca, and Mike Deodato) and Eternals (Kieron Gillen and Esad Ribic), Vader and Thanos share the core belief that has led them to victory in so many battles.
Published in 2015, Vader Down was hailed by many as one of the best stories Star Wars has ever told. While hunting Luke Skywalker, Vader is shot down over a secret Rebel base, stranding him in the middle of hostile territory with no back-up. Of course, Darth Vader conquers his enemies, slaughtering scores of foes in one of the greatest demonstrations of his power to date. In Eternals, Thanos is similarly outnumbered. Having been freed by the Eternal Phastos to bring an end to his immortal race, Thanos does battle with a group including Ikaris, Gilgamesh, and Sersi, whose godlike powers pose a threat even to the Mad Titan.
In both Vader Down and Eternals, fans get a chilling look into how Vader and Thanos see their enemies. In an iconic moment from the comic story, a Rebel soldier orders Vader to lay down his weapon, telling him he's surrounded. Vader replies, "All I am surrounded by is fear. And dead men." Despite their godly power, Thanos sees the Eternals in much the same way. The Great Machine - the embodiment of Earth's consciousness - explains, "Thanos does not think of 'battles.' Battles are for those who have peers. He thinks of slaughter and murder. There is him and endless victims." This concept of seeing those who stand against them not as enemies, but as the already dead, is a chilling philosophy that's part of why Darth Vader and Thanos are so unstoppable.
In the vast majority of their battles, neither Thanos nor Darth Vader conceptualize their enemies as equals, but simply as people they are about to kill. This sense of purpose - a twisted form of positive thinking - serves both well, lending them an air of superiority that's incredibly intimidating but also informing how they approach the challenge of victory. Having decided they're going to kill the people before them, the only decision left to Vader and Thanos is how best to do it.
Even when they're wrong, and their enemies prove to be equally deadly peers, Vader and Thanos show an uncanny ability to simply try again, choosing a new battlefield and new tactics. When he was defeated by Jedi Master Kirak Infil'a, Darth Vader recuperated and then returned to flood a nearby city, dividing the hero's attention and then killing him to claim his kyber crystal. Similarly, faced by a race of foes who are resurrected on death, Thanos adjusts his tactics, striking from the shadows to break down the Eternals' command structure and resources. Vader and Thanos have bested enemies who others would consider unconquerable, both because they possess superhuman wills and, Marvel makes clear, because they never doubt their eventual victory.
Of course, Kieron Gillen being involved in both Eternals and Star Wars: Vader Down also suggests that to some extent, readers are literally seeing the same philosophy at work, but Vader and Thanos put their own spins on this dark belief, with Thanos taking joy in demonstrating his superiority, while Vader never comes close to such a positive emotion. Darth Vader and Thanos are seen by many as unbeatable opponents, and in Vader Down and Eternals, it turns out they agree.