Ymir was a graduate of the 104th Cadet Corps, a former member of the Scout Regiment, and the inheritor of the Jaw Titan. She is a tragic and mysterious figure in Attack on Titan, known for her sharp wit, blunt honesty, and the deep bond she formed with Historia Reiss. Unlike many of her peers, Ymir carried with her the knowledge of the world beyond the Walls, having lived for decades as a Titan before regaining her humanity. 

Ymir was a tall and slender woman with sharp, intimidating brown eyes and messy brown hair often tied back into a ponytail with strands framing her face. She typically wore the Scout Regiment uniform, though she sometimes appeared in simple, casual clothing. When she was worshipped as a goddess in Marley, she wore a pale dress with her hair down.

Her Jaw Titan form stood at 5 meters, making it one of the shortest intelligent Titans. It had long arms, sharp fangs, and claws, along with rugged dark hair, pointed ears, and an oversized head, giving it a distinct, almost disproportionate appearance. Compared to most other Titan shifters, her Titan form bore fewer feminine traits and had a more beastly design.

At first glance, Ymir appeared selfish, cynical, and confrontational. She openly criticized others, especially when they tried to hide their true selves. Despite this harshness, she was extremely perceptive, able to read people with ease. Over time, her vulnerability was revealed, especially in her relationship with Historia Reiss, whom she protected at all costs.

Ymir’s defining trait was her pride. After regaining her human form, she vowed to live only for herself as a way of taking revenge against those who had used and despised her. Still, her actions often betrayed this philosophy, as she repeatedly risked her life for others, such as saving Historia, protecting her comrades, and even saving Erwin Smith despite blaming him for her failed plans. She lived between selfishness and sacrifice, making her one of the most morally complex characters in the series.

Early Life in Marley: Ymir was born a nameless Eldian orphan living in the streets of Marley. At the age of four, she was taken in by a man who gave her the name “Ymir,” after Ymir Fritz, and made her the center of a cult that worshipped her as a goddess. Though she embraced this role to give her followers happiness, the cult was eventually exposed by Marleyan authorities. Ymir and the cultists were punished—they were turned into Pure Titans and exiled to Paradis Island.

Life as a Pure Titan: Ymir wandered aimlessly as a Titan for nearly 60 years until the fateful night she encountered the Marleyan Warriors—Reiner Braun, Bertholdt Hoover, Annie Leonhart, and Marcel Galliard. She attempted to devour Reiner, but Marcel pushed him away and sacrificed himself. Ymir consumed Marcel and inherited the Jaw Titan, finally regaining her humanity.

Return to Humanity: After waking as a human for the first time in decades, Ymir found her way to the Walls and lived as a thief in secret. She later overheard a discussion about Christa Lenz (Historia Reiss), an illegitimate royal, and felt an immediate connection. In 847, she joined the 104th Cadet Corps with the hidden goal of protecting Historia.

Scout Regiment and Betrayal: During her time with the cadets, Ymir’s harsh personality often clashed with others, but she slowly grew to care for her comrades. She revealed her Titan power during the Battle of Utgard Castle to protect them, shocking everyone. Later, she sided with Reiner and Bertholdt, betraying the Scouts in order to secure Historia’s safety by aligning herself with Marley.

Fate: Despite claiming to live only for herself, Ymir’s final decisions were shaped by love and loyalty to Historia. She chose to leave Paradis with Reiner and Bertholdt, writing a heartfelt letter to Historia explaining her reasons. Ultimately, she returned to Marley, where her Titan power was stripped from her, ending her life.