副題の「Before the fall」とは、『進撃の巨人』本編第1巻で語られる「ウォール・マリア陥落の前」を意味する。物語は、エレン達が活躍する『進撃の巨人』本編の時代から約70年前から始まる。壁の中に進入を許してしまった巨人の吐瀉物の中から、一人の赤ん坊が発見された。やがて成長し、キュクロ(巨人の子)と名付けられた少年は数奇な運命を辿る。そして、彼は未だ巨人と戦うすべを持たなかった人類に希望をもたらす存在となっていく──。
突如出現した巨人の脅威から身を守るため、人類は巨大な城壁を築き、その内側を生存圏とした。そして三十年後、壁内の最も外縁に位置する街であるシガンシナ区は、巨人を崇める「巨人様」と呼ばれる狂信者が招き入れた一体の巨人によって蹂躙される。そして、巨人の嘔吐物の中にあった妊婦の死体から奇跡的に生まれた赤ん坊がいた。後に彼は「巨人の子」キュクロと呼ばれ、数奇な運命を辿る。
The subtitle “Before the fall” refers to “before the fall of Wall Maria,” which is told in the first volume of “Attack on Titan.” The story begins approximately 70 years before the era of the main story of “Attack on Titan,” where Eren and his friends play an active role. A baby was discovered in the vomit of a giant that had allowed its way into the wall. The boy, who eventually grows up and is named Kyukuro (giant’s child), has a strange fate. And then, he becomes a presence that brings hope to humanity, which has not yet had the means to fight against the Titans.
In order to protect themselves from the threat of giants that suddenly appeared, humans built gigantic castle walls and made the inside their survival zone. Thirty years later, Shiganshina Ward, the city located on the outermost edge of the wall, is overrun by a giant, brought in by a fanatic called “Titan-sama” who worships giants. And then there was a baby who was miraculously born from the corpse of a pregnant woman who was in the giant’s vomit. Later, he was called Kyukuro, “Child of the Giant,” and had a strange fate.