The concluding arc reveals that Ryu Seok’s terminal illness drives him to murder his own father, Chairman Ryu, who opposed the total extermination of the refugee populace. Ryu Seok captures Sa-wol to carry out a full bone marrow and blood transfusion, seeking to harness the youth's radiation-induced cellular mutation. Concurrently, 5-8, Major Seol-ah, and allied military forces execute a multi-front assault on the subterranean Core District, successfully rescuing Sa-wol before the procedure proves fatal.
In the final confrontation, Ryu Seok attempts to destroy the Core by initiating a catastrophic reactor meltdown. 5-8 shoots Ryu Seok point-blank in the head, leaving him to perish in the exploding facility. Following the collapse of Cheonmyeong Group, the surviving civilian government alongside the rebel Knights takes control of the infrastructure, abolishing the barcode caste system and establishing equal, universal oxygen distribution for all survivors.