Grisha Yeager

Dr. Grisha Yeager (グリシャ・イェーガー) is a doctor who lived in Shiganshina District before it fell. He is the father of Eren Yeager. It was said that he saved hundreds of lives from a plague that hit mankind.

Story
At the beginning of the story, Dr. Yeager is living in Shiganshina District with his wife, Carla Yeager; his son, Eren; and his adoptive daughter, Mikasa. He keeps the basement of his house locked and doesn't allow anyone inside.

After the fall of Wall Maria, a tearful Dr. Yeager injects a serum into Eren's left arm, which Eren believes is responsible for giving him the ability to shift into a Titan. Dr. Yeager tells Eren that the serum will cause memory loss and gives him the key to the basement, saying that all of the answers can be found there.

Dr. Jeager then disappeared, and has not been seen for five years since then.