The Yeager family (イェーガー家 Yēgā-ke?) is an Eldian family that lives both inside and outside the Walls. Most of them live outside, in the Liberio internment zone. One of them, Grisha Yeager, went inside and started a new family in Shiganshina District on the southern edge of Wall Maria; he also adopted Mikasa Ackerman in the year 844.
The Yeager family were descendants of Eldians who stayed in Marley after the Great Titan War. They lived in the internment zone in Liberio, where people like them were forced to stay by the government.
One day, Grisha and his little sister Faye left the ghetto without permission in order to follow a blimp flying in the sky. They crossed a town before eventually reached their goal. As they watched the blimp landing, two Marley soldiers noticed them and asked them if they had a permit exit to leave the Liberio internment zone. Grisha admitted they did not and chose to take his sister's punishment with his. One of them led Faye away while the second beat Grisha. When he got back home, Faye was not here. The two soldiers Grisha met earlier came and explained to the parents they found their daughter's body but did not know the cause of her death. In addition, they scolded them for their children's behavior and advised them to teach Grisha their ancestors' history, which Mr. Yeager did.
Years later, Grisha followed in his father's footsteps and became a doctor. He joined the Eldian Restorationists group after having heard the circumstances of his sister's death. Through his new activities, he met a young woman of the royal family named Dina. They got married and had a son they named Zeke.
A few years later, the Marley government announced they were at war with Paradis Island and were looking for Eldians children to become part of the army and host the power of the Titans. Grisha found a great opportunity for the restorationists and decided to make his son one of the chosen children. Thus he asked Zeke to become a double agent, pretending to be loyal to Marley whilst serving the cause of the Eldian Restorationists. However, Zeke eventually reported his parents to the Marley government. Along with the other restorationists, they were captured, tortured and sentenced to be turned into mindless Titans who would wander in Paradis Island. In return, Zeke would be raised by his grandparents under the mentoring of Tom Ksaver - the man Zeke would grow to see as his father figure.
After having witnessed his comrades and wife being turned into Titans and chase after their comrade, Grisha was saved at the last minute by Eren Kruger, the soldier who had beaten him fifteen years earlier. The latter appeared to be the chief of the Eldian Restorationists and a holder of the power of the Titans. He then proceeds to kill all the Marleyan soldiers and crush their boat. Once it was done, he set Grisha free, answered all his questions then charged him to continue the mission of their group. Grisha, at first reluctant, eventually accepted his mission and gained Kruger's powers.
Later on, Grisha was found wandering outside Wall Maria near Shiganshina District by Keith Shadis, with no other memories besides his name and the fact that he was a doctor. Shadis took him in and got him a job as a doctor in Shiganshina, where he also introduced him to Carla, who worked in the town as a waitress.
Sometime later, a plague hit Shiganshina and was cured by Grisha. After her parents and herself were cured, Carla thankfully embraced Grisha. Eventually, they got married and had a son, whom they named Eren.
In year 844, Grisha and Eren went to the Ackermans' house for a medical visit, and found that Mr. Ackerman and his wife had been murdered, and her daughter Mikasa had been kidnapped. Grisha went to call the police, and despite his warning to wait downstairs, Eren alone tracked the kidnappers down, killed two of them, and freed Mikasa. After the third kidnapper appeared and began strangling Eren, Mikasa awakened her dormant Ackerman power at Eren's urges and killed the criminal. Mikasa was then adopted by the Yeagers.
In year 845, after Eren and Carla have a discussion about Eren's wish to join the Survey Corps, Grisha promises him to show him an important secret he is hiding in the basement, and then leaves to work. A still upset Eren flees from the house and Carla sends Mikasa after him. But while the three are away from home, the Colossus and Armored Titans breach the Wall on Shiganshina and a flood of Titans invades the district. One of the debris that flies out of the Wall due to the Colossus Titan's kick falls on the Yeagers' house, destroying it and crushing Carla's legs. Despite Eren and Mikasa's attempts to rescue her, Hannes drags them from there when the Smiling Titan approaches. The kids then impotently witness as a helpless Carla is murdered and eaten by the Titan.
Later on that night, Grisha hears the news of the fall of Shiganshina and, enraged at the Reiss family due to their refusal to free humanity from the Titans despite possessing the power to do it, goes to the Reiss Chapel and faces the then holder of the Coordinate, Frieda Reiss. The two of them transform into Titans and fight, but Grisha defeats Frieda and eats her, murdering her and stealing the Coordinate. He then proceeds to slaughter the whole family, with the exception of Rod, who barely manages to escape, and Historia, who was living on a farm by then.Grisha then goes to the shelter where Eren and Mikasa are staying as refugees and learns from Eren that Carla has died. Grisha takes Eren into the forest and, as he gives him the key to the basement and instructs him to find it, by all means, he injects Eren with a Titan serum, triggering a transformation into a Pure Titan by Eren. The now mindless Eren grabs Grisha and bites him in half, inheriting his Titan transformation and Coordinate powers. After regaining his human form, Eren finds the remains of his father next to him and passes out in shock. He is later found by Keith Shadis, who takes him back to the shelter.
Eren later wakes up with no memory of that event as a side effect of the Titan serum, but he still retained the key and after that day he always wore it around his neck. The two kids and their best friend Armin Arlert apparently live alone for the next two years and helped in the fields. In year 847 they enlist in the 104th Training Corps and three years later, the three graduate and join the Survey Corps.
During the Battle of Shiganshina District, Eren crosses paths with Zeke, who recognizes and promises to save Eren after claiming they are both victims of Grisha. Eren, Mikasa, Levi, and Hange later go to the Yeager basement and find three books hidden in the false bottom of a drawer. The first contains a photograph of Grisha Yeager with a woman and a little kid, revealing he came from beyond the Walls. The books tell Grisha's story, beginning with the day his sister Faye was killed off.
After the Marley Mid-East War, Zeke reunites with his grandparents who praise him for carrying out his mission successfully. During Eren's infiltration into Marley in the year 854, he meets with his half-brother Zeke in a hospital. Together, they discuss Eren's inheritance of their father's memories, and Grisha's slaughter of the Reiss family. Eren claims to disagree with his father's approach, stating that Eldians would not have to suffer if they had not been born. With this, Eren agrees to Zeke's euthanasia plan and takes a baseball as a token of their agreement. Zeke also shares information beyond the understanding of Marley with Eren, such as about the true nature of the Ackerman clan.
Eren also meets his grandfather in hospital whilst under the guise of being an amnesiac war-veteran named "Kruger." They have a conversation about the Grice family, and Mr. Yeager asks Kruger to stop using Falco Grice for favors that could damage his family's reputation. He also tells Kruger to return to his family as soon as he is healthy. Eren notes Mr. Yeager seems to have regrets surrounding his own family. He is solemnly told that he regrets the fates his children met every day. Blaming himself because of the methods he used to raise his son, Mr. Yeager suffers a mental breakdown.
A few days later at Willy Tybur's speech, Eren Yeager has his name disgraced when he is declared to the world as the enemy of peace. In the resulting conflict, Eren inherits the War Hammer Titan, bringing a fourth Titan power into the possession of the Yeager family.