Invincible creator Robert Kirkman says fans are "finally going to get what they're asking for" in season 4, as Thragg escalates the Viltrumite threat

After three seasons of universal, multiversal threats, Invincible is (somehow) raising the stakes again in season 4. Entering the Invincible-verse for the first time this year is Thragg, the Grand Regent of the Viltrum Empire, and a moustachioed menace that makes Omni-Man look like an also-ran.

Voiced by Lee Pace, Thragg is effectively Invincible's Thanos – a threat so large it'll take the, ahem, assembled might of Mark, Nolan, Eve, and plenty more to stop him. For fans, an escalation in the show's Viltrumite subplot, which was largely put on ice after Nolan left planet Earth at the end of season 1, has been a long time coming, but that's all been by design according to co-showrunners Robert Kirkman and Simon Racioppa.

"We couldn't be more excited about how much of a culmination of the first three seasons this is going to feel like," Kirkman tells GamesRadar+. "There's this Viltrumite subplot that's been running through all the seasons that pays off in some really huge ways [this year]. Fans are always asking for more Omni-Man, and more Coalition of Planets, and more Allen and all that stuff. It's been drips and drabs in the show thus far because it's not the focus. The focus was establishing Mark and building Mark as a character and showing what's going on on Earth. But this season is different. This season, people are finally going to get what they're asking for."

While the threat of a Viltrumite invasion has been in the offing ever since Omni-Man massacred the Guardians of the Globe in the very first episode of the show, it wasn't until Conquest's arrival on Earth at the climax of season 3 that the near-unkillable Viltrumites once again became a clear and present danger. As for the casting of Pace – who famously played another intergalactic villain, Ronan the Accuser, in the MCU – Kirkman says there was no other choice.

"Lee Pace is just the greatest," Kirkman says. "We couldn't think of another actor to play Thragg. He was our first choice, only choice, and we couldn't be more thrilled that he was able to come in and do it."

"And also, he's the sweetest guy as opposed to Thragg in the show," adds Racioppa, with a smile. "You've seen little bits of the Viltrumites. You've met a couple of them, but we've also been like, 'They're coming. They're coming.' So, finally, we deliver on that promise."

Invincible season 4 streams on Prime Video from March 18. Make sure you never miss an episode with our Invincible season 4 release schedule, and while you wait, check out our list of the Best Prime Video shows.