Steven Yeun, popularized by his role in The Walking Dead, is set to make a significant leap from the land of the undying to a cinematic universe where people can't seem to die permanently in the Marvel Cinematic Universe. His role? Marvel's version of Superman.

Yeun's entry into the MCU as the Sentry, a character with a complex and intriguing background in Marvel comics, was a secret before it was initially unveiled by Robert Kirkman during an interview with comic book artist David Finch. This is Yeun's formal introduction to playing a live-action superhero after voicing Mark Grayson, the lead of Amazon Prime Video's animated show, Invincible, which is currently enjoying its second season.

Sentry, or Robert Reynolds, is a character that first appeared in Marvel comics in the year 2000 and quickly became a notable figure in the universe, interacting with groups such as the Fantastic Four, Spider-Man, and the Hulk. His story is a gripping narrative of a middle-aged, overweight individual who gradually recollects his past memories as the Sentry, a superhero possessing the power of "a million suns." His journey is marked by a confrontation with his archenemy, the Void, leading to a realization that both characters are two halves of the same person. This dual identity adds a layer of depth and conflict to the character, making Sentry's portrayal a potentially groundbreaking addition to the MCU.

Yeun's involvement in the MCU was confirmed to be part of the upcoming film, Thunderbolts, slated for release on July 25, 2025. Under the direction of Jake Schreier, Thunderbolts promises to deliver a unique experience different from past MCU entries. The film's ensemble cast includes notable names like Sebastian Stan, Wyatt Russell, Florence Pugh, Olga Kurylenko, Hannah John-Kamen, David Harbour, and Harrison Ford, among others. The inclusion of Yeun as Sentry adds another layer of anticipation for the film, promising a dynamic and possibly complex narrative.