Though the MCU has long been embraced as a superhero franchise that isn’t ashamed to show its comic book origins, the cinematic universe still has a tendency to be a little more down-to-Earth than its cartoonish source material.
One clear example of this is Avengers: Infinity War’s slightly more grounded explanation of the backstory and motivations of Thanos. In particular, the movie suggests a very different origin for the purple tyrant’s popular nickname, the Mad Titan.
In the comics, Thanos is referred to by this title because he comes from the moon of Titan and was driven insane (or “Mad”) after falling love with Death herself. This explanation, however, was rejected for the movies, possibly because it seemed a little goofy even by MCU standards.
Instead, the “Mad” part of Thanos’ nickname takes on a slightly different meaning in Infinity War. Specifically, this is the madness of a radical doomsayer who proposed killing half the population of Titan in order to avoid a coming disaster.
While speaking to Doctor Strange, Thanos himself even recalls how his fellow Titans called him “a mad man” for suggesting such drastic measures, but once his catastrophic predictions came true, the Mad Titan was more convinced than ever that genocide was the right solution to the universe’s biggest problems.
You could therefore argue that Thanos’ nickname is inherently rooted in his key motivation as a villain. While everyone else may call him “mad” for his bleak vision and his extreme methods, the tyrant remains convinced that he’ll some day watch the sun rise on a grateful universe.
Of course, things didn’t exactly turn out as planned for Thanos, whose victory at the end of Avengers: Infinity War proved short-lived, but given the character’s ongoing popularity, we certainly can’t rule out a comeback somewhere down the line. Who knows? Maybe he’ll some day meet Mistress Death after all.