Devil of All Earth

Artwork consistently renders the Devil as a huge crouched shape wearing a menacing grin. The storybook Frieda Reiss shares with Historia hides it beneath a heavy hooded cloak, its lipless mouth crowded with pointed teeth, while the volume read to young Grisha Yeager bares its head to show goat-like horns, a lengthy tail, claws, heavy musculature, and tapered ears.

A bronze monument in Liberio, depicting the hero Helos running the Devil through, softens the design considerably: bearded, full-haired, and hornless, closer to a Titan than a demon.

According to the myth, a girl named Ymir Fritz met this being some eighteen centuries before Wall Maria fell and struck a bargain whose price is never recorded. What she received made her the first of all Titans. Eren Kruger dismisses the story as a fabrication, quite possibly planted by the enemies of Ymir's people, believing she instead gained her power at the so-called source of all living matter, and Eren Yeager's later journey through Ymir's memories in the paths shows no trace of any Devil.

The wider world long treated the creature as real, celebrating the Marleyan hero Helos for supposedly slaying it during the Great Titan War, until Willy Tybur publicly admitted the Helos legend was propaganda. Frieda Reiss retells the fable to her half-sister Historia with the heroine renamed Krista, holding her up as a model of lovable kindness, and the Survey Corps rediscovers the tale years later inside Grisha Yeager's basement journals. The bitter irony, the story eventually reveals, is that the real bargain was struck not with a demon but with King Fritz, who exploited the enslaved Ymir's powers and took her as a concubine.

Within the legend, the Devil's single feat is granting the power of the Titans, the gift that transformed Ymir Fritz and seeded every Titan that followed. Belief in that act is the reason the Subjects of Ymir are condemned across the world as the children of the Devil.