The Russo brothers recently revealed that they had cut the Thanos backstory from The Avengers: Infinity War, which for whatever reason, seemed to tick off a lot of fans.
The good news is that The Avengers: Infinity War featured just enough backstory from Gamora and the short scene on Titan with Thanos using the Reality Gem. I’ll also add that the footage with young Gamora turned out really well, much to my surprise.
Now VFX supervisor Matt Aitken reveals details on the Thanos backstory that was cut (via Screen Rant):
Originally there had early on been a longer sequence that we were going to be involved in that was a longer flashback to the original Titan, which explained in more depth Thanos’ motivations and what’s driving him, but they ended up boiling it down to [what’s in the movie]… It’s essentially telling the same message but in a more concise format, with this more handful of shots.
We were prepared for that more in-depth look of Titan, should we have done that. Yes, Thanos is a little bit of a mutant of his own people. They’re not humans in color but they’re not as bright purple as he is and not as tall as he is and they don’t have the same chin that he has. So, yeah, he definitely, he was designed and the other Titan residents to accentuate that difference for sure.
In the comics, Thanos gets his looks as a result of having a mutant Deviants gene, while the other Titans are Eternals. The Eternals were created by the Celestials who performed genetic experiments on early humans, and two branches were created, the Eternals and the Deviants.
Interestingly enough, an Eternals movie has been rumored, which Infinity War could have helped introduce by including a peek at the Eternals on Titan in a flashback scene, but Marvel chose not to go that route. Infinity War did make mention of Thanos’ father, with I think it said Mentor (though I thought they might have said Eros, who is Thanos’ brother in the comics).
Regarding the MCU backstory of Thanos, Kevin Feige and Josh Brolin previously touched upon it in interviews:
“He’s from a planet called Titan that’s no longer inhabited because of things that he thought he could help prevent, and he was not allowed to do that,” Feige told EW.com. “What he feared most happened, and the planet and everybody on it basically went extinct. He vowed not to let that happen again. He thinks he sees the universe going down the tubes. He thinks he sees life expanding outward unchecked. That will bring ruin, he believes, to the universe and to that life.”
This is what Brolin had to say about seeing a younger Thanos:
“He’s different from his family,” Brolin said. “They’re all Titans and they all look similar, but he was born deformed. You see how he grew up, you see he was like the Quasimodo of this time, or if you’ve ever read Perfume [Patrick Süskind ‘s 1985 novel about a serial killer who craves beautiful scenes but is disgusted by the smell of humanity], it’s a great parallel to Thanos. He stuck out. He was an anomaly. He was a freak. And that lent to this apparent insanity.”