The upcoming Thunderbolts film from Marvel Studios is slated to introduce one of the most powerful characters Marvel Comics has ever produced, the Sentry. Essentially, he’s Marvel’s Superman, but with a dark secret. He’ll be portrayed by actor Lewis Pullman in the upcoming MCU film. But who is this (relatively recent) Marvel character, and what is his strange origin story, both on and off the page?

The Bizarre Backstory of Marvel Comics’ Sentry

Art by Jae Lee from Paul Jenkins' original Sentry mini-series from 2000.
Marvel Comics

The Sentry began his comic book existence as an elaborate trolling by Marvel Comics editorial. Back in the ’90s, the Marvel Knights line of comics helped save the company after bankruptcy. Edgy titles like Kevin Smith’s Daredevil got critical acclaim and big sales. In 2000, creators Paul Jenkins and Rick Veitch came up with the Sentry series for Marvel Knights, about a superhero in a more classic DC Comics mode than a Marvel one. His costume suggested Superman’s, or Shazam’s. Although he’s not the only analog for Superman at Marvel (Hyperion predates him) he is the most powerful. He may be stronger than Superman himself.

Sentry, The “Lost” Stan Lee Marvel Hero

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When the Sentry mini-series was announced, Marvel touted the series as a discovery of a “lost” concept by Stan Lee and a forgotten artist named Artie Rosen from the early ’60s that never made it to print. When Rosen “died” in 1999, writer Paul Jenkins discovered his original creation with Lee, a classic hero named the Sentry. He decided it was time to give the hero a proper Marvel debut in his own mini-series. Marvel EIC Joe Quesada even used the octogenarian Stan Lee himself as part of the promotion, giving interviews to comic book media about how even he had forgotten he co-created this hero. Of course, all of this was complete nonsense. Sentry was a pure creation of Jenkins. The whole backstory was a marketing gimmick.

Sentry Is Marvel’s Superman, with a Dark Side

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In the Sentry original limited series, we meet Robert Reynolds. He’s an out-of-shape, middle-aged man living a bleak existence. Reynolds starts remembering a superhero career in his younger days, when he was the Sentry. Having taken “the Golden Sentry Serum,’ an advanced version of Captain America’s Super Soldier Serum, he now had “the power of a million exploding suns.” His arch nemesis was a dark presence called “The Void.” He was a contemporary of early Marvel heroes like the Avengers, Spider-Man, and the Fantastic Four. In fact, he was very close friends with Reed Richards, the Fantastic Four’s genius leader. As he encountered each Marvel hero in the present, they all slowly began to remember him. But why did they forget him in the first place?

After a deadly attack by the Void that resulted in high casualties during his heroic heyday, Sentry disappeared from the Marvel Universe when his mind was wiped, along with the memories of everyone on Earth, to make everyone forget that he ever existed. This was because of Reed Richards and Doctor Strange realizing that the Void was not just Sentry’s arch-foe, he was also a part of him. The only way to get rid of the Void was to make everyone forget that both Sentry and Void existed, including Bob Reynolds himself. So for years, he lived a life of anonymity, forgetting his heroic past entirely.

Sentry Becomes the Mightiest Avenger

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In the New Avengers series in 2005, writer Brian Michael Bendis brings Sentry back to the Marvel Universe. We see Reynolds in a cell inside the supervillain prison the Raft, where he has voluntarily imprisoned himself for murdering his wife, Lindy Lee. When a huge jailbreak occurs, the Avengers catch several of the escaping villains. During this time, Daredevil finds the Sentry, and the powerful hero saves several others from Carnage, whom he flies into space and rips in half. Later, the Avengers discovered that X-Men villain Mastermind, who was at fault for Jean Grey’s descent into Dark Phoenix, was responsible for what happened to Sentry. He implanted a psychic virus in Robert Reynolds’ mind that created the delusion of the Void, but it was all really an aspect of his own repressed personality, unleashed by the serum.

Readers learned that the psychic virus does not allow Reynolds to remember his life as he lived it. Instead, he subconsciously implants his memories into the mind of comic book writer Paul Jenkins, a meta-commentary on the real-life creator of the same name who invented Sentry. Eventually, the Avengers show Reynolds that his wife, whom he confessed to murdering, is still alive. Sentry runs away, going to a house in the suburbs he shares with his wife Lindy. The Marvel heroes find him there, and attempt to reason with him. But he insists the Void is coming, and will destroy the world. Ultimately, X-Men telepath Emma Frost frees Reynolds from the psychic virus and restores his memories, and the Sentry joins the Avengers. The rest of the world does not regain their memories of Sentry. To them, he’s a brand new hero and new addition to the Avengers.

The Many Powers and Abilities of Sentry

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The Sentry is one of the most powerful superheroes in the Marvel universe, even more powerful than his DC counterpart Superman. His powers supposedly came from a more advanced version of Captain America’s super soldier serum. Later, they revealed that an alien intelligence actually infused itself with the serum, making Reynolds its host body. Whatever the true origins are, Sentry has super strength, enough to subdue the Hulk at his most powerful. He can fly, has super speed, has telepathy, and can even shapeshift. He can also project light and project energy blasts. Sentry can also pass on a portion of his power, as he did to his kid sidekick, Billy Turner, a.k.a. Scout, an amalgamation of DC’s Robin and Captain Marvel. Jr. He even passed on powers to his Welsh Corgi, Watchdog, a riff on DC’s Krypto the Superdog. Sentry is the definition of the phrase “OP.”

Sentry’s Death and Rebirth

Sentry remained an Avenger for many years, although he constantly battled the emergence of the Void, a symptom of his own mental illness. Eventually, he joined former Green Goblin Norman Osborn’s Dark Avengers, as Osborn’s secret weapon. Thanks to Norman’s mental manipulations, he is able to break down the barriers that keep Robert Reynolds’ darker Void persona at bay. In the Siege storyline, Osborn and the Dark Avengers, together with Loki, attack Asgard itself. Osborn uses the powers of the Sentry to destroy Asgard, which was hovering above Oklahoma at the time.

Marvel Comics

The Dark Avenger Ares, the actual Greek god of war, attacks Sentry for his loss of control. Then, Sentry literally rips the god in half. (It’s a pretty gross panel too). Sentry then murders Loki, although he is eventually reborn as Kid Loki. Realizing what he’s done, upon reverting to his Bob Reynolds persona, Sentry asks the Avengers to kill him. Thor obliges, and carries his body to the sun to be cremated. But Sentry is effectively immortal, and can’t truly die. He eventually merges his Sentry half with his Void half, now seemingly more in control, but also elevated to godhood. In the comics, it seems it is the destiny of the Sentry to effectively never die.

Sentry in the MCU

All we know about Sentry in the MCU is that he’s part of the upcoming Thunderbolts film. We have no idea what role he’ll play, but we imagine a scenario similar to the comics. We foresee a situation where Sentry is assigned by the government to the Thunderbolts team. Perhaps to be their public face? But when the ultra-powered hero loses control of his darker half, the former assassins will have to find a way to stop him. But that’s just us guessing. We’ll know for sure when Thunderbolts hits theaters in 2025.