Attack on Titan Vol. 21 — Manga Raw / Buy Official

Levi faces the ultimate choice of which of the dying men—Erwin or Armin—to inject with the Titan serum. Hange and Eren want Erwin revived, but Levi ultimately chooses Armin, resurrecting him as the inheritor of the Colossal Titan. Erwin dies quietly, holding the ideals of a soldier in his heart. Bertholdt is devoured by Armin and perishes. The surviving group finally reaches the basement and discovers the books and key left by Eren's father, Grisha. Inside is proof that humanity exists beyond the walls—a fact that overturns every prior assumption and leads into the world's truth being unraveled in the next volume.