Several decades before the fall of Shiganshina District, a ferocious Titan enters Shiganshina due to the actions of a fanatical cult. Chaos ensues, and from the consumed corpse of a pregnant woman, a boy named Kuklo is born. Shamed and disgraced for presumably being the son of a Titan, Kuklo faces hardships throughout his early life and is eventually purchased as a trophy for a noble family in Wall Sheena. There he meets Sharle Inocencio, a nobleman's daughter, who teaches him the history and ways of the people of the Walls.

With determination in his heart, Kuklo decides that he must free himself from his bondage and set out beyond the Walls to prove to himself and the world that he is not a Titan's son. Little does he know, Kuklo's journey will bring him into the ranks of the Survey Corps itself, leading to great changes for humanity in their struggle against the Titans.