Grisha Yeager

Grisha Yeager was an Eldian doctor who originated from the Liberio internment zone in Marley, and was one of the Eldian Restorationists. He was sent on a mission from "the Owl" to infiltrate the Walls and take the Founding Titan from the Reiss family, and was given the power of the Attack Titan in order to do so. Grisha was taken inside the Walls by Keith Sadies, and settled in the Shiganshina District. He documented the details about Eldia, Marley, the Titans, and his past in three books that he hid in his basement.