Invincible, the Prime Video adult animated series created by Robert Kirkman, was confirmed to return for a fourth season in July 2024. The show follows Mark Grayson's (played by Steven Yeun) journey as he juggles the responsibilities of a superhero with being a teenager, as he is guided by his father, Nolan Grayson (played by J. K. Simmons), also known as the superhero Omni-Man.
In March 2025, the show confirmed that it would return for season four sometime in 2026, that voice acting had been completed, and that Thragg had been cast. But we weren't told who has been cast as Thragg.
Just a few days back, the show announced on Instagram that it has been renewed for season five as well. Additionally, the show confirmed that Matthew Rhys had been cast in seasons four and five, but his role was kept secret. As theories go, fans have reacted to speculations that suggest that perhaps Matthew Rhys has been cast as Thragg in Invincible seasons four and five.

Fans speculate about Matthew Rhys potentially being the voice artist behind Thragg in Invincible seasons four and five
Thragg is the Grand Regent of the Viltrum Empire in Invincible, the most powerful pure-blooded Viltrumite, and a key antagonist in the series. Born during Emperor Argall’s golden age, Thragg was groomed for leadership and later became obsessed with restoring Viltrumite supremacy after the empire’s fall.
He is ruthless and fanatical and sees Mark and Nolan as traitors and does everything to destroy them. Thragg has immense strength, unmatched speed, durability, and regeneration powers, which place him above even Conquest and Omni-Man.
He is about to be the show's biggest antagonist and is set to appear in seasons four and five. Invincible and Omni-Man will face Thragg along with the other superheroes in the two upcoming seasons. While there's quite a buzz around the character, creators have not yet confirmed who will voice it.
Media and news outlet ScreenTime made a post on X stating,
Matthew Rhys has been cast in ‘INVINCIBLE’ Season 4
Followed by the question
Could he be Thragg? 👀
Fans have rushed to reply to the post with their reactions and speculations.
One fan (@thegolden_eel) wrote,
"Name a better Thragg. You can’t"
Another fan (@BensonGeek) noted how both Matthew Rhys and Thragg have a distinct mustache and wrote,
"Well, he's got the mustache"
One fan (@movies_vault) pointed out a small similarity between Rhys and Thragg, saying,
"If he’s Thragg, season 4 is gonna be 80% monologues and 20% trauma."
Rhys is a successful actor, known for his portrayal of Phillips Jennings in The Americans, for which he received a Primetime Emmy Award for Outstanding Lead Actor in a Drama Series in 2018. Besides, he is also famously known for playing Lloyd Vogel in A Beautiful Day in the Neighborhood.
Thus, it seems the fan is speaking from his experience watching the actor's past performances.
Another fan (@Abhinav∅5655123) wrote,
"If he’s Thragg… we’re about to witness absolute carnage."
Invincible season four comes out in 2025, and a release date for season five is yet to be revealed. Invincible is streaming on Prime Video.
For more articles like this, follow Soapcentral.