In 875, mankind achieved its final victory.
In the same year, a large-scale virus broke out inside the wall. The strongest human beings sealed the city wall at the last moment to prevent humans who had migrated outside the wall from being infected by the IC virus, but they themselves were trapped in the wall full of zombies.
In 878, the original 104th Survey Corps returned to the wall filled with zombies, looking for survivors and IC pathogens. But when he was forced into an underground street by zombies, he met Levi, the strongest human being who was trapped inside the city wall two years ago to seal it off.
"What do you mean?"
"I mean, now we have to be careful not only of the infected, but also of Levi."
"Huh? Commander, why..."
"You also noticed something is wrong with Levi. What is he now? Is he the strongest human being in the past, or is he a walking dead possessed by the IC virus? Or..."
"There were two people inside him."