Viltrum's Cataclysm

Viltrum's Cataclysm is the decisive clash of the fourth season, pitting a Coalition of Planets strike force led by Thaedus against a handful of Viltrumites under Grand Regent Thragg on their own homeworld. The event closes out the Viltrumite War and sets in motion the surviving Viltrumites' migration to Earth. By the time it begins, the Coalition has spent the war slowly grinding down the Empire, using rare weapons and individuals able to actually wound Viltrumites, freeing world after world and thinning an already dwindling species.

Hoping to end the war in a single stroke, Thragg had launched a surprise raid on Talescria, the Coalition capital, made possible by a traitor who disabled its defenses. The strike devastated the city but was ultimately repelled, partly thanks to the Graysons arriving in time. Once the captured mole confessed that Thragg had pulled back to Viltrum to regroup, Thaedus recognized the retreat as a rare opening and assembled the Coalition's strongest fighters for a preemptive assault on the enemy's heart.

The strike team, including Thaedus, Nolan, Mark, Oliver, Battle Beast, Allen, and Tech Jacket, slipped toward Viltrum, unaware that Thragg had hidden warriors among the billions of corpses forming the planet's ring. The ambush sprang the instant they cleared it. The battle turned bloody, with many Viltrumites falling as their weaknesses were exploited, aided by Space Racer's Rognarrs, the Infinity Ray, and Tech Jacket's specialized darts. Nolan tried to reach Thragg directly and was swatted down to the surface, where the Grand Regent offered him amnesty and a chance to rebuild the Empire. Nolan refused, insisting the species had doomed itself, and Thragg answered by hurling him back into space.

Thragg then crippled Oliver, tearing off his jaw and one arm, and brutalized Mark when he charged in vowing to repeat what he had done to Conquest. Changing tactics, Nolan rallied the survivors behind Space Racer and aimed the Infinity Ray at the planet itself. He, Mark, and Thaedus rode the beam straight into the wound it carved, punching through Viltrum's core and dragging its molten interior out the far side. The strain shattered the world entirely, and it burst apart, scattering the combatants across a spreading debris field.

With the homeworld gone, Thaedus called for surrender, but a grief-stricken Thragg answered by decapitating him on the spot. He then beat Nolan and Mark nearly to death, impaling the father and gouging out the son's eyes, only to relent at the last moment, unwilling to add more Viltrumite deaths to his conscience. He abandoned them in the wreckage and vanished into space with his remaining loyalists. General Telia later recovered the three Graysons and brought them to Talescria for weeks of treatment, and Allen took temporary command of the Coalition. When told the surviving Viltrumites had disappeared from known space, Mark realized in horror that they had gone to Earth.

The battle reduced the Viltrumite fleet to a single cruiser and left only thirty-seven pure-blooded Viltrumites alive, Nolan among them. It also marked the third apocalyptic act Thaedus committed against his own people. In a change from the comics, where Thaedus was the one who spearheaded the homeworld's destruction, the show hands that role to Nolan.