Spoiler alert! This article contains spoilers for Thunderbolts*.

With Sentry, Thunderbolts* has finally brought one of Marvel Comics’ most powerful and complex characters to the big screen – though with some changes to his origin story. Thunderbolts* introduced Lewis Pullman as Sentry, AKA Bob, the unstoppable Golden Guardian with a malevolent second personality known as the Void. While the basics of Bob’s story were accurately adopted, there were some alterations that changed the nature of Sentry’s character.

The MCU timeline’s band of misfit antiheroes are brought together early in Thunderbolts*, whereupon they meet the seemingly innocuous Bob. Bob’s bumbling antics subsequently bond the team, aiding their escape from Valentina Allegra de Fontaine’s furnace-vault, while also causing them to confront their inner torment (albeit inadvertently). His later turn as the Void brought that same ragtag troupe even closer – Bob included. Bob’s origin is therefore tied to the genesis of the MCU’s Thunderbolts* team, which differs from the comics.

Sentry’s Marvel Comics Origin Story Explained

Sentry first appeared in The Sentry #1 (2000), introduced as a “forgotten” superhero from the early Marvel Universe. Created by Paul Jenkins and Jae Lee, Robert Reynolds was a seemingly average man who discovered a secret formula – the Golden Sentry Serum – hidden away in his garage. Upon ingesting it, he gained the power of “one million exploding suns,” becoming the Sentry, Earth’s mightiest superhero.

However, Sentry’s heroic career was retroactively erased from public memory due to the emergence of his dark alter ego: the Void. A manifestation of his repressed mental illness and darkest impulses, the Void brought mᴀss destruction wherever it went. For every life saved by Sentry, the Void would take one. As a result, Doctor Strange and Reed Richards helped erase Sentry from history, including his own memories, to protect the world.

Later stories expanded on his origin, revealing that he was a mentally ill teenager refused entry for an experimental drug programme known as Project Sentry. This was an attempt to recreate the Captain America Super Soldier Serum. Determined to find a thrill, Robbie breaks in and ingests highly concentrated Super Soldier serum, imbuing him with god-like powers.

These stories further explore Bob’s fragile psyche, revealing that his powers were linked to schizophrenia and dissociative idenтιтy disorder. Sentry was at once a Superman-level figure and a deeply broken man, often portrayed as both savior and threat in equal measure. The MCU rendition retains these essential facets but connects them more with the movie’s overarching themes and tone.

Sentry’s MCU Origin Story Explained

In the MCU’s Thunderbolts*, Robert “Bob” Reynolds is introduced not as a forgotten legend, but as a man broken by a traumatic past. The film reveals that Bob suffered through a childhood marked by physical and emotional abuse at the hands of his father. As an adult, Bob turned to drugs to cope with his trauma, spiraling into a meth addiction that left him vulnerable and isolated.

It’s during this dark period that Bob travels to Asia, where he volunteers for an experiment by the shadowy corporation OXE. Overseen by Valentina Allegra de Fontaine, the OXE group are conducting illegal super-soldier experiments. It was likewise known as Project Sentry, and had thus far been a failure, with Bob even scheduled for incineration alongside the Thunderbolts team.

It wasn’t until Bob revealed his powers that the Sentry project was considered a success at all, though it was fraught with complications. As Mel explained, give a man as virtuous and indominable as Steve Rogers the Super Soldier serum, and his nobility and morality are amplified. Give a man as troubled as Bob the serum, and the negative aspects are amplified. Indeed, when Sentry begins having god-like delusions and even threatens Valentine, a killswitch inside him is activated, inadvertently awakening the Void.

This is the crux of the changes the MCU made to the Sentry’s origin: he is the victim of other peoples’ actions. Sentry in the comics was borne from internal conflict and poor choices (or luck). The MCU’s Sentry was abused, battered, experimented on, warped into becoming a hero he wasn’t built to be, and then finally pushed over the edge when his failings came to light. The MCU’s Sentry was forged through external adversity; the comic book Sentry was largely created by his own actions. This difference is key and plays right into the central themes in Thunderbolts*.

Why The MCU Origin Story Is Better

The MCU’s Sentry origin strips away the comic book nostalgia and myth-building in favor of a gritty, personal story that mirrors the themes of Thunderbolts*. Bob’s struggle isn’t just about controlling power – it’s about overcoming trauma, addiction, and the fear that one is irredeemable. This resonates more directly with the grounded tone and character-driven narratives that have defined Marvel’s recent Phase 5 entries. By making Sentry a victim of abuse, addiction, and experimentation, Thunderbolts* humanizes him in a way that makes his duality with the Void more tragic and less abstract.

The MCU’s approach aligns with the movie’s broader themes: Yelena grapples with the grief of losing her sister Natasha, Bucky with decades of manipulation, and Ghost with being used as a weapon. In this context, Bob isn’t just a superpowered man with a dark side — he’s a mirror of the team’s collective trauma and an emblem of the governmental overreach that has hampered each of their lives. It’s no longer just about good vs. evil within one man; it’s about whether healing is possible after irreparable harm.

This is exemplified in the love-conquers-all ending in Thunderbolts*, in which the team embrace Bob to defeat the Void. This allowed each of them to grieve for their respective lives while giving Bob the love and support he never had. This allowed him to retake control of his body, and makes him a much more compelling character.

Is Bob Really Still Sentry In The MCU?

The post-credits scene in Thunderbolts* suggests that Bob’s powers are very much intact, but he chooses not to use them. While the rest of the New Avengers team discuss matters, he stays out of the action, living simply as Bob. However, the whole team, Bob included, were confirmed to return in Avengers: Doomsday, so this could change.

It’s unlikely Marvel Studios will leave Sentry in the background for long, especially with Dr Doom looming large in the MCU’s future. With a multiversal and/or cosmic threat teased in Thunderbolts*, Sentry may have to return. Whether he likes it or not, the Sentry still lives within him, and the MCU might not survive without him.

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  May 2, 2025
  

  
  
  
  

  
  

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