Warning: This article contains spoilers for Captain America: Brave New World.

Marvel Studios could have explained Sentry’sThunderboltsdebut inCaptain America: Brave New World, but the upcomingMCUmovie now has a challenge to explain Robert Reynolds' origin story. Lewis Pullman replaced Steven Yeun inThunderbolts‘cast in January 2024, and the trailers for the highly-anticipated crossover movie have confirmed he’ll be portraying Sentry, who made his first Marvel Comics appearance in 2000.Robert Reynolds’ Sentrywill be one of the MCU’s most powerful characters yet, and his origin could connect to several heroes in the franchise’s history.

Sentry glowing with energy in Marvel Comics

The mostrecent trailer forThunderbolts*, released during this year’s Super Bowl, proved that the titular team of antiheroes and reformed villains would be going up against the Void, a dark being living inside Robert Reynolds' superpowered body. TheVoid is a truly terrifying villain, demonstrated by his supreme strength and ability to turn humans into shadows, but the origins of this dark alter ego are yet to be revealed.Marvel Studios could have usedCaptain America: Brave New Worldto explain Sentry’s origin story, but missed a trick, instead leavingThunderbolts*to do the work.

Sentry’s Comics Origin Makes Him A Super-Soldier

Robert Reynolds Made His Marvel Comics Debut In 2000’s The Sentry #1

When Robert Reynolds first appeared in Marvel Comics,he was revealed to have been a classic superhero as the Sentry, fighting alongside the likes of the Fantastic Four, the Hulk, Doctor Strange and more. His memory and the memories of everyone on Earth were wiped to save the planet from the Void inside Sentry, and while this action was taken again, Sentry soon returned and became a permanent fixture in Marvel Comics. His full origin story was explored in 2010, revealing him to be a former meth addict who broke into a laboratory and consumed a super-soldier serum.

This wasn’t any old super-soldier serum, as Project: Sentry was developed to create a serum that would give its user powers one hundred thousand times stronger than Captain America.The Golden Sentry Serum gave Robert Reynolds the power of a million exploding suns, making him the most formidable super-soldier ever seen in the Marvel Universe. This could connect him to several characters from the MCU’s history, butCaptain America: Brave New Worldfailed to use its best villain to confirm thisorigin story for Lewis Pullman’s Sentry.

Daniel Bruhl’s Baron Zemo tightens his glove and mask in front of the Thunderbolts, Captain America, and Red Hulk.

The MCU Just Killed The Best Theory For Sentry’s Origin

Sentry Could Have Been Connected To President Thaddeus Ross' Experiments

It would have made a huge amount of sense to connect the Sentry toThaddeus “Thunderbolt” Ross in the MCU, given the latter’s obsession with attempting to recreate the super-soldier serum that first enhanced Steve Rogers into Captain America in the 1940s.This origin story has been heavily theorized since Lewis Pullman was expected to be playing Robert Reynolds, prompting speculation thatCaptain America: Brave New Worldwould hint at the Sentry’s debut. However, despite Ross' prominent role inBrave New World, this did not come to pass.

I Can’t Believe Captain America: Brave New Worlds’s Ending Made My Wildest Thunderbolts* Theory More Likely To Happen

Captain America: Brave New World’s ending and post-credits scene may have an exciting implication for Thunderbolts*' potentially dark aftermath.

Harrison Ford assumed the role of Thaddeus Ross inCaptain America: Brave New World, allowing the character to become the President of the United States despite the tragic passing of his original actor, the late William Hurt.He was revealed to have been working with the imprisoned Samuel Sterns for the past 16 years, shuffling him into a position of power and influence, but also leading to him transforming into the Red Hulk. Ross has tried to make manysuper-soldiers over the years, including Bruce Banner and Emil Blonsky, and Sentry could have been the culmination of his life’s work.

Bucky Barnes in Thunderbolts* trailer and Sam Wilson fighting Red Hulk in Captain America Brave New World poster

Tim Blake Nelson reprised the role of Samuel Sterns inCaptain America: Brave New World, coming back following the tease of his evolution into the Leader in 2008’sThe Incredible Hulk.

Thaddeus Ross could have easily used the Leader’s expertise and knowledge to perfect a working super-soldier serum. Sterns' work with gamma radiation and genetic modification means he should be perfectly primed to have designed the Golden Sentry Serum, allowing Robert Reynolds to be enhanced. It seems this isn’t the case, however, asCaptain America: Brave New Worldmade no mention of Reynolds or Ross' super-soldier experiments. This leaves the door open forThunderbolts*to do some explaining regarding exactlywhere Robert Reynolds' Sentry came fromand who gave him his powers.

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So How Can Sentry Still Be A Super-Soldier In The MCU?

Thunderbolts* Will Explain Sentry’s Origin Story

Of course, it’s very possible that Robert Reynolds could still be depicted as a super-soldier inThunderboltseven without Thaddeus Ross' involvement. Many super-soldiers have come into existence in the MCU separate from Ross, including the Winter Soldier, Isaiah Bradley, the Red Guardian and the Flag Smashers.Someone else could have used fresh eyes to create a perfect super-soldier serum, and this honor could have fallen to Julia Louis-Dreyfus' Valentina Allegra de Fontaineand the scientists atOXE, which will debut inThunderbolts.

Ant-Man and the Wasp(2018)

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The Falcon and the Winter Soldier(2021)

Olga Kurylenko

Black Widow(2021)

Lewis Pullmans' Robert Reynolds seems to be found in an OXE facility inThunderbolts*‘trailers, one hidden in the middle of nowhere where several Thunderbolts members are gathered. Here,plans for the Sentry’s logo, his base of operations, the Watchtower, and his costume and appearance can also be seen, suggesting OXE built Sentry from scratch. Valentina’s connection to OXE suggests this organization could be a subsect of the CIA, which actually implies President Ross would have known about Reynolds’ enhancement - perhaps his final secret.

I Need Thunderbolts* To Include 1 Major MCU Cameo After Captain America: Brave New World

Captain America: Brave New World has made me even more desperate to see one MCU hero make a cameo appearance in Marvel’s upcoming Thunderbolts*.

President Ross has a lot of skeletons in his closet, and many of these came to the forefront inCaptain America: Brave New Worldas the Leader put his plans into motion.Robert Reynolds' evolution into Sentry could have been yet another mistake that Ross would prefer to be cleaned up, which could constitute a visit to the Raft inThunderboltsto hear the incarcerated Ross explain himself. Sentry is one of the most exciting and formidable characters debuting in the MCU’s Phase 5, so it would be great to see his full origin story explored inThunderbolts.

Avengers 5 Concept Poster

Spider-Man Brand New Day Logo Poster

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