What Have I Done?

The penultimate chapter of the third season adapts the Invincible War. Believed dead after Mark crushed his skull, Angstrom Levy clung to life and was rebuilt by three mysterious Technicians. Months later he opens portals across the globe and looses roughly eighteen evil variants of Invincible from other dimensions, each tethered to a drone so he can watch and steer them. He offers them anything they crave in return for maximum destruction, his true aim being to make the whole world fear and hate the real Invincible.

As the alternate Marks rampage through major cities, the mainstream Invincible and Atom Eve throw themselves into the fight, joined by heroes worldwide. Mark quickly realizes Angstrom is behind it despite believing him dead. Oliver suits up as Kid Omni-Man over Debbie's objections, while at the Pentagon, Cecil and Donald learn the attackers are weaker than their own universe's Invincible and mobilize every available hero after the noisemaker weapons and their labs are destroyed.

The three-day siege is brutal. Heroes fall in droves as the variants tear through them. Nogogglesible massacres much of the Guardians before Darkwing II sacrifices himself to drag the killer into the Shadow-Verse, and Omnivincible shatters Eve's leg, forcing Mark to carry her to safety and stay at her side. The bloodiest loss comes at Teen Team HQ, where a fatally wounded Rex Splode reaches into his own body, grips his skeleton, and detonates himself to kill Gogglesvincible after getting Rudy and an unconscious Amanda clear. The Hunk, Darkwing II, and Rex all die, while Eve, Dupli-Kate, Immortal, and others are left gravely hurt.

By the third day, only eight variants remain, and Angstrom gathers them above the Grayson house. When they turn on him over his broken promises, he double-crosses them all, hurling every one of them into the Wasteland Universe. Cecil then teleports the real Invincible in to confront him. Mark fights through swarms of drones and nearly captures Angstrom, but a final drone loosens his grip; the closing portal severs Angstrom's arm as he escapes. Bleeding out, Angstrom begs the Technicians for help, only for them to refuse, subdue him, and declare that he now works for them.

The war leaves cities from New York and Los Angeles to Tokyo, Paris, and Moscow in ruins with staggering casualties. A recovering Immortal chooses to give up hero work and commit to a life with Kate. Consumed by guilt and blamed openly by Powerplex, Mark refuses Cecil's offer to lead the Guardians. His brief moment of calm ends when the Viltrumite Conquest descends to test Earth's progress, and a furious, grieving Invincible charges straight into the fight.

The title references a Cecil line from issue 50, though it is never spoken here, likely chosen to avoid spoiling the war. The episode marks the final appearances of Rex Splode, the Hunk, and British Knight, as well as the last time Aaron Paul voices Powerplex, a role he stepped away from because the story affected him emotionally.