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The Fritz family (フリッツ家 Furittsu-ke?) is an ancient royal bloodline of humanity, going back unbroken for 2,000 years. After the raising of the Walls, the Fritz family within the Walls became known as the Reiss family.
Around 2,000 years ago, the Fritz family came into power as the royal bloodline of humanity. Over these next two millennia, their lineage would be destined to remain unbroken. At some point during their rule, the Ackerman family becomes the guarding force of their monarchy, serving as the protectors of the monarchs.
Over a century after the family's rise into power, Ymir Fritz is said to have made a deal with the Devil of the Earth. Through this bargain, Ymir was given the power of the Titans. With her power, she made great advancements for her people, and when she died her "soul" was split between Nine Titans, who would go on to found the nation of Eldia. Her greatest power, the Founding Titan, would be inherited by the monarchs of the Fritz family for many centuries to come.
After some time, the eight Titan clans subservient to the Fritz family begin to fight amongst each other, though throughout the years the Fritz family maintained order with the power of the Founding Titan. However, when the 145th King of the Fritz family came into power and received the Founding Titan, he chose to abandon the never-ending conflict in the Eldian Empire and instead moved the capital of Eldia to the island of Paradis off the east coast of the continental mainland. In the King's absence, the Marleyan minorities in Eldia seized the opportunity and sparked the Great Titan War in Eldia, capturing seven of the nine Titans and overrunning the continent.
As Eldia lost more and more of its land, King Fritz gathered as many members of the Fritz family as he could to the island of Paradis, along with the fleeing peoples of Eldia. However, some members of the Fritz family strongly disagreed with the King's decision to abandon the Eldian-Marleyan conflict and stayed behind on the continental mainland. Once the Eldians willing to flee were gathered at Paradis, the King used the power of the Founding Titan to erect three concentric Walls around their territory on Paradis and erased the memory of the world from the Eldian people. From that point onward, the Fritz family in the Walls would be replaced in name by a false line of monarchs, while the true royal family would take the new name of the Reiss family.
Over eighty years after the end of the Great Titan War, Dina Fritz was the last remaining descendant of the Fritz family within Marley. She would be sent by the Owl, an Eldian spy within the Marleyan military, to join the cause of the Eldia Restorationists. There she met Grisha Yeager, who had gained significant influence in the Restorationist movement, and together they made plans to retrieve the Founding Titan from Paradis and restore the nation of Eldia. They married the following year and hand a son named Zeke, who they insisted would be the King of Eldia. However, Zeke ended up turning against the Restorationists at the age of seven after Grisha sent him to join the Marleyans' warrior program, hoping that he would be a double agent. Dina would then be turned into a mindless Titan, pledging in her last moments that she would find Grisha no matter what became of her. Zeke would remain in the warrior program, rising through the ranks to become the war-chief of the warriors.
Thirteen years after wandering as a Titan, Dina was among the many Titans that invaded Shiganshina District in the year 845 when the Colossus Titan and Armored Titan breached the gates of Wall Maria. She wandered throughout the district until coming to the home of the Yeager family, where Carla Yeager, Grisha's second wife, lay helpless beneath the rubble of their ruined home as her son, Eren and her adopted daughter, Mikasa attempted to free her. As a Garrison soldier carried the children to safety, Dina pulled Carla out of the rubble, eating her as any normal Titan would.
Twenty years after Dina Yeager was made into a Titan, Zeke infiltrates Wall Rose and with his power as the Beast Titan turns the residents of Ragako village into Titans, spreading chaos throughout the territory for reasons unknown. He leaves Wall Rose later that night as members of the Survey Corps desperately fight his Titans.
Two months after his departure from Wall Rose, Zeke reunites with his warrior subordinates Reiner Braun and Bertolt Hoover in the ruins of Shiganshina District. The two argue with Zeke for the sake of their comrade Annie Leonhart, who had been captured two months ago, and Zeke challenges Reiner to combat for the decision. Reiner loses, and Zeke determines that they will instead wait in Shiganshina for the Survey Corps to arrive so that they can take the Founding Titan, known to them as the Coordinate.
When the Survey Corps arrives at Shiganshina, Zeke and his warriors battle with them both within and around the district. Zeke makes use of his Beast Titan to deal heavy damage to the Survey Corps, fatally wounding their commander Erwin Smith, but he is defeated by Levi Ackerman. During his retreat, Zeke encounters his half-brother Eren Yeager. Before they part ways, Zeke promises Eren that he will one day return to save him.
Eren Yeager and the surviving members of the Survey Corps learn of the Fritz family and their connection with both the history of the Walls and Eren's father Grisha. After learning of his father's past, Eren begins to see his father's memories in his dreams due to their shared inheritance of the Coordinate, and Eren realizes that Dina Fritz was the Titan who ate his mother.