Initially revealed to have joined the super-powered franchise back in February, who exactly Yeun will be playing has remained a secret.
Yuen called his MCU role an "interesting" one, but little by way of official information has been made public on the actor's casting.
However, rumors point to The Walking Dead star taking on the Marvel Comics superhero Sentry (aka Robert Reynolds), a hero with Superman-like powers who grapples with an internal evil alter ego known as the Void.
Steven Yeun's MCU Role Confirmed
The Walking Dead creator Robert Kirkman let slip who Thunderbolts star Steven Yeun will be playing in the MCU.
While it was known Yeun would be a super-powered character of some sort in the storied franchise, it had not been confirmed who exactly he would bring to life on-screen.
Speaking with comic artist David Finch, Kirkman revealed, "My good friend Steven Yeun is playing the Sentry in a movie:"
Kirkman: "My good friend Steven Yeun is playing the Sentry in a movie."
Finch: "I saw that, yeah. That’s coming up. That’s gonna be pretty exciting."
He continued on to say that he'd just talked to Yeun about a "costume fitting" for the character he had just gone to, joking he "[didn't want to] get anybody in trouble:"
“Yeah he called me, he went in for a costume fitting. I hope I’m not…I don’t think this is a spoiler or anything that will get anybody in trouble. I don’t know, maybe. We’ll see. I don’t care. I don’t work for Marvel. What are they going to do to me?"
Kirkman recounted how Yeun had to call him to jokingly say, "I guess I only do superheroes that are yellow and blue," as the actor is currently voicing Mark Grayson/Invincible in Kirkman's Invincible series:
Yeah, he called me and he said, 'I just came back from a costume fitting for the Sentry. I guess I only do superheroes that are yellow and blue.' He said he was at the costume fitting and was like, 'Aww, crap. I forgot Invincible was yellow and blue.'"
How Will Sentry Play in the MCU?
While this is not an official announcement by any means, one can assume Robert Kirkman is telling the truth, meaning Steven Yeun will play Sentry in the MCU.
There has been no confirmation of who the main villain of Thunderbolts (the film in which Yeun will make his Marvel Studios debut), and Sentry could be a logical possibility.
The character is best known for his exploits as a superhero. So, introducing him as a villain, being consumed by the dark voice known as the Void could be a fascinating twist for a character that is said to play a major part in the MCU going forward.
This "bucket list" role for Yeun could take quite some time before fans ever see him as a true blue superhero.
This conflict of, 'Is he a hero or is he a villain?' could make for some interesting narrative fodder, as the franchise hurdles towards its next Avengers-level even in Avengers: The Kang Dynasty and Avengers: Secret Wars.
For now, though, fans will just have to wait until Marvel Studios pulls the curtain back on Yuen's super-powered character officially confirming Yeun's superhero persona.
Steven Yeun is set to appear in Thunderbolts when it hits theaters on July 25, 2025.