Ep. 4: Rentaro battles Kagetane and fires Heaven's Ladder railgun against a Stage Five Gastrea.

4

Rentaro and Enju confront Kagetane and Kohina in the bay area after finding civil officers slaughtered. Rentaro breaks Kagetane’s Varanium barrier, refuses his call for war, and survives an abdominal wound by using Sumire’s experimental AGV drug to regenerate. He then defeats Kagetane with Varanium-enhanced martial arts. A Stage Five Gastrea appears outside the Tokyo Area, forcing Kisara to have Rentaro activate the Heaven's Ladder railgun. Due to system errors, Rentaro uses his left Varanium arm as a projectile to manually fire the weapon and destroy the threat. He later finds Kayo dying from defending the area and ends her suffering. Rentaro accuses Kikunojo Tendo of orchestrating Kagetane’s actions. In the epilogue, Seitenshi refuses to reveal the origins of the Gastrea. Rentaro gives Enju her corrosion exam results, which appear normal, though her actual corrosion rate far exceeds what he reported.