Eren
Jaeger

Eren watched a Titan pull his mother out of the rubble of their home in Shiganshina and eat her while Hannes carried him away. The vow he made that day, to kill every last Titan in the world, is the thread the whole story hangs on. Even before the wall fell he was the kid who called life inside it living like cattle and wanted the Scout Regiment while every adult around him called that suicide. Losing his mother did not create that anger. It gave it a target.

Trost turned him into something no one had a category for. A Titan bit off his leg, then swallowed him whole when he pulled Armin out of its mouth, and he tore his way back out inside a Titan body of his own. He carried a boulder to the breach and sealed it, stood trial for what he was, and got handed to Levi's squad on the open understanding that Levi would kill him if he turned. The Female Titan slaughtered that squad in front of him anyway. Then Reiner and Bertholdt, two friends from his own class, admitted on top of Wall Rose that they had broken it five years earlier. On the day the Scouts bled themselves dry rescuing him from them, Eren punched the Titan that killed his mother and discovered he could command the mindless ones, a power that only worked because that Titan carried royal blood.

The basement gave him his father's memories instead of a weapon. Marley across the sea, Eldians in internment zones, both the Attack Titan and the Founding Titan sitting in his own spine, and a thirteen-year limit that left him under eight. The Attack Titan can glimpse the memories of the people who will hold it next, and at the medal ceremony after Shiganshina, the moment he kissed Historia's hand, Eren saw what was coming. He spent four years walking toward it. He entered Marley as a wounded soldier, let a kind boy carry his letters, and killed Willy Tybur in the middle of the speech that declared war on Paradis, then ate the War Hammer Titan while his friends fought a raid he had arranged without asking them.

Zeke believed Eren was his partner in a plan to sterilize their own people. Eren played along exactly long enough to reach the Paths, refused him there, and freed Ymir Fritz by treating her as a person with a choice instead of a tool. Then the walls came down. The Rumbling flattened the world beyond the island, eighty percent of humanity by his own count, so that no power would be left to destroy Paradis and so the friends who stopped him could stand before the survivors as heroes. Mikasa cut his head from his Titan's mouth and kissed him. The power of the Titans ended with him, and she buried him under the tree in Shiganshina where he used to nap.