Every MCU Villain Plot Ranked From Worst To Best
1. Wiping Out Half Of Existence - Thanos (Avengers: Infinity War)
Thanos' role in the MCU, and ultimately his plot in Infinity War, began way before the movie hit in 2018. He was behind Loki's attack in Avengers Assemble, he was behind Ronan in Guardians of the Galaxy, and he popped up during the end credits of both Age of Ultron and Thor: Ragnarok.
This six year wait, and the character development that came with it, helped to make Thanos the best villain in the franchise, as did Josh Brolin's excellent performance. But it was the why of the Mad Titan that made him such a compelling villain.
While some, like Malekith or Dormammu, wage war basically for the sake of it, there was true logic and meaning behind Thanos' conquest. Unlike the comics, in which he is obsessed with death, the antagonist does what he does to save the universe. He truly believes what he is doing is right, and it's easy to see why. After snapping his fingers the first time, knowing he would be tempted by them again, Thanos destroyed the stones. A genocidal monster with integrity and honour.
The villain may have killed half the population of the universe, but he did it completely at random, for the greater good of the surviving half. For all we know, the Mad Titan only survived due to random luck. He likely didn't even protect himself from the snap, considering how indifferent he was to his own death when it came.