|According to these notes, we are the "Subjects of Ymir," a special race from the nation known as Eldia who are capable of becoming Titans. These Subjects of Ymir once ruled the world, and could possibly rule it again. That is why the world...attempts to eradicate us, the Subjects of Ymir.|
|— Hange Zoë relays the truth found in Grisha's basement|
The Subjects of Ymir (ユミルの民 Yumiru no Tami?) are an ethnic group descended from Ymir Fritz and the only race capable of becoming Titans. Beginning with Ymir and her three daughters, the bloodline eventually expanded across the Eldian people, to the point of majority. Currently, they populate the Walls of Paradis Island and the internment zones found in Marley and other nations of the world.
The Subjects of Ymir are descended from Ymir Fritz herself, the first human to acquire the power of the Titans over 1,800 years ago. After Ymir's demise, her daughters Maria, Rose, and Sheena Fritz devoured her corpse and gained her ability to turn into a Titan. As per their father's commands, Ymir's daughters reproduced to expand the bloodline and continue the race of humans who can turn into Titans. The Subjects of Ymir conquered the old nation of Marley using the Nine Titans and established the Eldian Empire, which over the centuries would come to rule the mainland continent of its origin.
About 600 years ago, an epidemic plagued much of the world; killing so many that the population plummeted. The King at the time used the power of the Founding Titan to rewrite how the bodies of the Subjects of Ymir were designed to overcome the pandemic.
The rule of the Eldian Empire lasted until the end of the Great Titan War, which resulted in Marley's resurrection as a nation and Eldia's capital being moved to Paradis Island. The land surrounding the new capital of Eldia would later be surrounded by three concentric Walls raised through the guidance of the Founding Titan. On the mainland, Marley gathered the Eldians, and placed them into internment zones such as within Liberio. They were spared eradication due to their ability to be turned into Titans for war purposes, as the Eldian Empire had done during its reign. On the island, the Subjects of Ymir had their memories of the world outside the Walls erased by the Founding Titan. The Eldians of other races were unaffected by the Founding Titan, so the royal family either granted them the privilege of living inside Wall Sheena in exchange for their silence, such as the fake Fritz family, or persecuted them as in the case of the Ackerman and Azumabito families. Other countries around the world also placed Eldians into internment zones; the treatment of Eldians in those countries is far worse than the treatment of Eldians in Marley.
Titans and Paths
The Subjects of Ymir are the only living beings capable of transforming into Titans. Some of them will also inherit the Nine Titans. If one of the Nine Titans is not transferred before dying, the Titan will be sent to a random baby among the Subjects of Ymir, with distance and blood relation playing no factor. This led to the discovery that all Subjects of Ymir are connected by paths, and these paths connect all Subjects of Ymir to the Founding Titan.
If a Subject of Ymir reproduces with an individual of another ethnicity, the offspring will be a Subject of Ymir. An example of this is Reiner Braun, the illegitimate son of an Eldian mother and a Marleyan father. Another example is Mikasa Ackerman, the daughter of an Asian mother and an Ackerman father. According to Marley, the Eldian Empire had forced other races to have their children, to produce more Subjects of Ymir.
Subjects of Ymir can be identified through blood testing.
In the year 848, Ilse Langnar of the Survey Corps became the last surviving soldier of the left flank of the 2nd brigade during the 34th Expedition, lost in Titan territory within Wall Maria. With her vertical maneuvering equipment broken and horse missing, she chose to record her experiences as she made her way north toward Wall Rose. During her journey, she is caught by a Titan who forces her back against a tree but refrains from eating her. The Titan speaks to her, first believing her to be "a Subject of Ymir" before mistaking her for "Lady Ymir" herself. Ilse attempts to communicate with the Titan while taking notes, asking what it is, where it comes from, and, after losing her composure, furiously asks why they eat humans. The Titan only responds with pained moaning and later starts ripping off its cheeks when Ilse screams at it. When she attempts to flee, the Titan catches her and crushes her head between its jaws, but does not consume her body. Her notebook and remains were discovered a year later by Hange Zoë and Levi Ackerman.
Upon uncovering the secrets of Grisha Yeager's basement following the Battle of Shiganshina District, the surviving members of the Survey Corps learn of their ethnic identity as Eldians and as Subjects of Ymir, a race despised by all peoples of the world. This news, along with the many remarkable truths found in the basement, become a much-discussed topic among people of varying opinions within the Walls.
Following the Marley Mid-East War, the Warriors of Marley begin to grow concerned over the fate of the Eldians, and by extension the Subjects of Ymir, particularly in the world's growing desire to see them exterminated in order to end the Titan threat. Capturing the Founding Titan remains in high priority, though Pieck acknowledges that this alone will not save the reputation of the Eldians. In an effort to shed a positive light on the Eldians and to do away with the threat posed by the people of Paradis Island, Zeke Yeager collaborates with the Tybur family, who agree to make a public announcement in favor of the Eldians during a festival in Liberio. At this time, they will convince the nations of the world that Paradis Island will be conquered within a year.
Soon afterward, the Tybur family comes to Liberio. As Commander Theo Magath and Lord Willy Tybur discuss the affairs of their nation, Lord Tybur expresses the regret he and his ancestors have felt for the fate the Eldians have been burdened with in the past century. Desiring to set things right for his nation, Lord Tybur offers to work with Magath towards the betterment of Marley.
One month later, the time of the festival approaches. On the eve of the festival, Willy acknowledges the world's shared hatred for the Eldian people, announcing that by the end of the festival he will announce his plan to solve the crisis posed by the Eldians and the Titans.
About one month later, back on Paradis Island and following Marley's surprise attack on the island for the raid on Liberio, Eren Yeager manages to come into physical contact with his royal-blooded half-brother, Zeke Yeager, allowing him access to the Founding Titan's powers. Eren uses them to unleash the countless Colossus Titans within the Walls to destroy the outside world, telepathically addressing all Subjects of Ymir using the Founding Titan to declare his intentions.
- In modern times, the Subjects of Ymir are often simply called "Eldians" (エルディア人 Erudia-jin?). While this is generally true as most Eldians are Subjects of Ymir, the two terms are not entirely synonymous.
- According to Reiner Braun, Bertolt Hoover, and Annie Leonhart, the false king and the nobles who ruled the interior of the Walls are Eldians of another race. This confirms that, even in modern times, not all Eldians are Subjects of Ymir.
- The Association to Protect the Subjects of Ymir argues that the Subjects of Ymir from other nations beyond Eldia and what is now Marley deserve protection because they are not Eldians, have never been Eldians, and are only victims of the Eldian Empire's historic force-breeding. This means that not all Subjects of Ymir are Eldians. In fact, Ymir Fritz herself was not an Eldian.
- Pieck asks Gabi Braun if they are Eldians or Marleyans before answering that it does not matter which because the bottom line is that they are "Subjects of Ymir," a race who can turn into Titans. This suggests that "Subjects of Ymir" is their race whereas "Eldian" is their ethnicity or nationality. This is further emphasized when Mikasa Ackerman reminds Kiyomi Azumabito that she is an Eldian, regardless of her Asian blood.
- At the height of the Eldian Empire, being a Subject of Ymir was proof of high status in non-Eldian countries. However, after the Eldian Empire's collapse, having Subject of Ymir blood is condemned upon, even among the remaining Eldians who are not Subjects of Ymir.
- The Ackerman clan is the byproduct of the old Eldian Empire's fiddling with the Subjects of Ymir.
- Although the Ackerman clan are Subjects of Ymir, they are somehow unaffected by the Founding Titan's memory altering power. For this reason, Kenny's grandfather mistakenly believed that they are not Subjects of Ymir. The Survey Corps were also unsure if the Ackerman clan are Subjects of Ymir, or if they can become Titans.