The Mad Titan Thanos originally narrated Avengers: Infinity War. At a screening of the film, co-directors Joe and Anthony Russo revealed that an early version of the script once included a voiceover from Thanos.
In the first part of Marvel’s much-anticipated third Avengers film, Thanos (Josh Brolin) garnered a significant amount of acclaim as a villain with a compelling backstory and complex motivations in a franchise that doesn't always offer much character development to its villains. Thanos was described by Marvel Studios President Kevin Feige as being the main character in Avengers: Infinity War, and it so happens that his presence in the movie was even more significant than how he was presented in the final cut.
At a two-hour screening and Q&A event for Avengers: Infinity War hosted by Collider, the Russo Brothers explained that one of the earliest drafts for the film featured a non-linear version of the story that was narrated by Thanos. The script also included backstories for the Black Order, but it came in at 250 pages, prompting the brothers to say, “Alright, we can’t fit all this storytelling.” However, the draft wasn’t completely abandoned. As the brothers explained:
“I think writing out Thanos’ narration gave us insight into who he was as a character and what we wanted him to do in this film. So then it was much easier once we started pulling all that out to make it subtext for him as a character, and to make a more linear structure.”
Not only did the early draft of the script help create an interesting villain, it also helped to shape the final structure of the film. With Thanos’ goal of stealing the Infinity Stones, the directors realized that it had the structure of a heist film and ended up using that general structure to simplify their 250-page script. Ultimately, Thanos' journey spoke for itself, making the narration unnecessary.
Thanos first debuted in the comics in 1973 and is one of the most powerful villains in the Marvel universe. As Marvel moved from page to screen - making a lasting impression on modern filmmaking - Thanos' journey to collect the Infinity Stones and wipe out half the universe didn't only culminate in Avengers: Infinity War, but gave the villain just as much - if not more - attention than the Avengers themselves. The film gave him arguably noble intentions (improving the world by decreasing its numbers) and genuine emotion towards his adopted daughter Gamora (Zoe Saldana), even if he proved that love in an unorthodox way.