One Of Peter Cullen's Final Performances Is In This Beloved Superhero Show
by Witney Seibold · /FilmOn August 26, 2026, voice actor Peter Cullen passed away at the age of 85. Cullen was perhaps best-known for voicing Eeyore in several iterations of Disney's "Winnie the Pooh" cartoons, and as the voice of Optimus Prime, the heroic robotic leader of the Autobots on the 1984 TV series "The Transformers." Cullen continued to play Optimus Prime for many years, most recently in the live-action 2023 film "Transformers: Rise of the Beasts." His deep, authoritative voice is well-known to generations of kids, and his passing is a tragedy in the voice acting world.
Cullen's career, of course, extended far beyond Eeyore and Optimus Prime. Throughout the 1980s, Cullen racked up an enormous volume of credits, playing additional voices on "The Smurfs," the Incredible Hulk on "Spider-Man and His Amazing Friends," Mario in "Saturday Supercade," the evil K.A.R.R. on "Knight Rider," and Airborne on "G.I. Joe: A Real American Hero." He was in "Muppet Babies," "Ghostbusters," "Teenage Mutant Ninja Turtles," and dozens of others. Kids heard his voice everywhere.
Cullen's final TV credit was playing Thaedus, another wise yet troubled leader in the vein of Optimus Prime, on the hit superhero animated series "Invincible." He appeared in seven episodes of the show, including "Don't Leave Me Hanging Here," which aired in April 2026.
Playing Thaedus in Invincible was one of Peter Cullen's final roles
"Invincible" follows the eponymous superhero crimefighter, also known as Mark Grayson (Steven Yeun), as he adjusts to having newfound ultra-powers. Mark is the son of the powerful superhero Omni-Man (J.K. Simmons), who belongs to an alien species called the Viltrumites, and has secretly been plotting to subjugate Earth on behalf of the Viltrumite Empire. Based on the comics of the same name by writer Robert Kirkman and artists Cory Walker and Ryan Ottley, "Invincible" is very much a show for adults, and contains a lot of violence. The series debuted in 2021, and it's been highly acclaimed ever since.
The character of Thaedus, played by Peter Cullen, first appeared in the Season 2 episode "This Missive, This Machination!" Thaedus was once a higher-ranking warrior within the Viltrumite leadership, until he assassinated the Viltrumite emperor Argall in the hope of ending his people's violent ways. Thereafter, Thaedus founded an organization called the Coalition of Planets in order to curtail the Viltrumite's plans to conquer all other worlds.
Thaedus was different from his fellow Viltrumites in that he believed other species to have value. He was dignified and wise, but carried great guilt over the damage done by the Viltrumites. In an action that he would also come to regret, Thaedus developed a bioweapon called the Scourge Virus, designed to infect and kill only his own species. He was always resolute, and Cullen's aged voice lent a great deal of authority to Thaedus. But he was also a badass, capable of smashing faces into pulp as the situation required.
Thaedus was a great final character for Peter Cullen
"Invincible" is a series that pushed superhero concepts to further extremes, both in terms of violence, and in terms of justice. Thaedus believed that committing genocide on his own people was a just action.
Optimus Prime looms large in many people's imaginations, emerging as both a collected hero and a capable soldier over the course of the "Transformers" franchise. Cullen has said in interviews that he based the voice of Optimus Prime on that of his brother, a veteran of the Vietnam War. That authority, paired with a confident gentleness, continued to get Cullen work for years. He was a good choice to play a resolute and powerful ultra-soldier in search of redemption on "Invincible." As he aged, Cullen's voice began craggier (it happens to us all) which, to my ear, only made his performances more powerful. Thaedus' voice is sonorous and booming, with Cullen wailing and snarling his way through fight scenes with the energy of a man a quarter his age.
Cullen's Eeyore, meanwhile, taught many younger children about the persistence of sadness. Eeyore is a depressive, self-pitying donkey who serves as a downbeat counterpoint to the flighty, distracted childishness of Winnie-the-Pooh and the other animals in the Hundred-Acre Wood. He was often incapable of being cheered up, and little kids might be able to relate to that, especially when they're having big feelings. Cullen was a thoughtful hero and a warrior, but also a gentle, melancholy soul. He was many things, and he will be missed. R.I.P., sir.