Ice Queen

Recovering in the Briggs infirmary, Edward learns he narrowly avoided frostbite because his flesh meets conductive automail, and that his destruction technique failed on Buccaneer's cold-climate prosthesis of composite materials. Olivier Mira Armstrong, openly scornful of her brother, presses the boys on why they came and why Alphonse's armor is empty. The brothers offer a trimmed account that omits the homunculi and the Führer, and Armstrong keeps them only because alkahestry interests her as a potential weapon. She assigns Major Miles to show them the fort and put them to work.

Miles removes his sunglasses to reveal the red eyes of an Ishvalan, testing Edward, who answers that people should be judged as individuals. Miles explains how Armstrong values his mixed heritage and once vowed to duel him personally if his blood could not forgive Amestris. The tour lands the boys on icicle-clearing duty under a newly promoted Vato Falman, then continues down to the weapons division and the fort's power core, just as engineers report a strange digging sound from below.

A massive, ouroboros-marked man matching the homunculus Sloth tunnels up through the bedrock. Gunfire bounces off him harmlessly, and he blunders through the base toward the research level. Armstrong herself assaults him with a bazooka and then a tank, finding that only cannon fire barely dents his self-repairing body. The Elrics shield bystanders and confirm the creature is human in makeup and not from Drachma. Told this, Armstrong calls for tank fuel, announcing she will halt the monster with something worse than fire and show it the power of Briggs.

Edward learns why the cold nearly maimed him and why his alchemy failed on Briggs automail. Olivier Mira Armstrong keeps the Elrics for her interest in alkahestry and assigns them to Miles. Miles reveals his Ishvalan ancestry and tests Edward's attitudes on race. Vato Falman resurfaces as a Briggs second lieutenant. The homunculus Sloth burrows into the fortress, resisting bullets, bazooka fire, and tank shells with rapid regeneration. Armstrong confirms he is human-made and calls for tank fuel to stop him.

The episode draws on the manga chapters covering the ironclad rule and the snow queen. The title-card array is the Ouroboros, and this is the first appearance of Alphonse's helmet with shortened hair. The tanks fielded against Sloth are modeled on the German PzKpfw IV, a World War II medium tank.