Why Thanos Was In The Marvels Trailer, But Not The Movie
Summary
- Marvel Studios used MCU footage of Thanos and the Avengers to market The Marvels, but those characters don't appear in the movie.
- Dar-Benn shares similarities with Thanos in her philanthropic beliefs and brutal methods, as she only wants to restore Hala and the Kree to their former glory.
- Although Dar-Benn's goals are similar to Thanos', she lacks the patience and strategy that made Thanos an effective supervillain in Avengers: Infinity War and Avengers: Endgame.
Although The Marvels featured MCU footage of Thanos and the Avengers in its final trailer, they weren't anywhere in the actual movie. Taking place in the MCU timeline's present day, The Marvels continues stories set up in Phase 4 releases like WandaVision and Ms. Marvel, as well as the Infinity Saga's Captain Marvel and Avengers: Endgame. Naturally, The Marvels' cosmic plot touches upon certain events from those MCU titles, but the 2023 movie is still a standalone film focused on Carol Danvers, Kamala Khan, and Monica Rambeau.
The Marvels follows the titular heroes' attempts to stop a tyrannous villain, Zawe Ashton's Kree Accuser Dar-Benn, from destabilizing the universe in her quest to bring her people to their former glory. However, The Marvels also deals with the overarching story of the MCU's Multiverse Saga, as Dar-Benn's actions cause rifts in the fabric of reality, leading Monica Rambeau to end up in a different universe altogether during The Marvels' multiversal post-credits scene. These potentially catastrophic consequences may raise some comparisons with a villain as powerful and ambitious as Thanos.
Marvel Studios Used Thanos To Sell The Marvels 
The final trailer for The Marvels opens with footage from previous MCU movies, namely The Avengers, Captain Marvel, and Avengers: Endgame, featuring characters such as Iron Man, Captain America, and Thanos. As Dar-Benn is presented onscreen, Thanos' voice states "My work is inevitable. There will always be more… to finish it." This trailer sets up Dar-Benn to continue Thanos' mission to bring balance to the universe. Hence, including the MCU's most popular villain in the trailer for a movie where the main villain has the same philosophy was a logical marketing choice, even though The Marvels doesn't show where the Avengers are and doesn't add anything new to Thanos' MCU story.
Dar-Benn Believed She Was Like Thanos 
Since Dar-Benn seeks to restore Hala and provide the Kree with basic resources, it's impossible not to see parallels between her seemingly philanthropic goals and those of Thanos in Avengers: Infinity War. Dar-Benn sees her planet's slow death in front of her eyes and finds herself unable to help it through any means that aren't brute force. On top of that, she has a single person to blame: Captain Marvel, who placed Hala on a path to destruction when she destroyed the Supreme Intelligence — not unlike Thanos, who blamed Titan's downfall on those who didn't believe his cataclysmic predictions.