Some Avengers: Endgame fans have complained that the Thanos we saw in the movie was a less complex, more one-dimensionally villainous version of the nuanced character we got in Avengers: Infinity War, complete with a badass new sword. But no matter how he came across in the sequel, Thanos was still the same person, still motivated by the same philosophy, and still imbued with the same single-minded devotion to his cause.
In fact, it was this devotion that resulted in one of the most unsettling scenes in Endgame. If you’ll recall, Nebula goes back in time to the past and is captured. Using her memory, the Mad Titan catches a glimpse of the future. A future in which he’s having his head decapitated at the hands of Thor.
Instead of showing fear or anger though, Thanos reveals a small smirk as he watches his life’s final moments. On the film’s commentary track found on the recent digital release, co-director Anthony Russo offered his insight into why that scene makes sense, saying that it’s the villain’s “vindication.”
“[Yeah], it’s just confirmation that he is on the right track,” added Markus. “This moment is one of my favorite moments in the movie, where Thanos gets nothing but satisfaction from seeing his head chopped off.”
“Well I think that’s always what Thanos supporters online say, what is exciting to them about his as a character is his monastic dedication to his mission. And he is willing to die for the mission,” said Joe Russo.
So, it seems that the entire point of that scene had been to establish that this younger Thanos was just as deeply committed to his cause as his older self. So much so that watching himself die after fulfilling his mission of ending half of all life in the universe aroused only feelings of satisfaction within him for a job well done. This further goes to prove that the Mad Titan, far from being a one-note villain that fans have accused him of becoming in Avengers: Endgame, is still the same Thanos on a holy mission to bring about world peace through force that we saw in the earlier movie.
The creative team behind the film have also speculated that audience reaction in the form of laughter when Thor decapitates Thanos, while a surprising reaction, could be a form of nervous shock, brought about as a result of seeing the biggest MCU threat of all time be eliminated during the first few minutes of the movie.