| The subject of this article has no official name.|
It is a fan-given name as substitute for lack thereof, and should not be considered as part of the Attack on Titan universe.
| This article is incomplete.|
Please feel free to edit this article to add missing information and complete it.
Specifically, it needs images.
The Titan is a 5 m class with long, black hair, very large irises and an agile, muscular, chimpanzee-like body. This form grants Ymir rather long arms and sharp claws. The smallest intelligent Titan known yet, this Titan form has a mouth with all pointed teeth, as well as sharp claws that can either be used to grasp on to things or for combat.
At some unknown point in time, Ymir gained the power of the Titans. During the Wall Rose invasion, Ymir is among the recruits of the Scout Regiment at Utgard Castle when it is overrun by Titans commanded by the Beast Titan. When their commanding officers die confronting the Titans, Ymir speaks with Christa, reminding her of a promise they made to each other during their training days. Taking a knife from Conny, Ymir slits her palm and transforms to fight the Titans at the base of the castle.
In her Titan form, Ymir begins to slaughter the Titans around Utgard with ease, using claws on her hands and feet to slash at napes as well as making use of her fanged teeth. After a short while, Ymir's Titan is outnumbered and overwhelmed and nearly breaks the structure of the tower. Rather than risking the castle's collapse, Ymir allows for her Titan to fall into the horde until Christa calls out to her, telling her that she should destroy the castle if that is what it takes to survive the Titan horde. Ymir then starts tearing away at the tower, using bricks and stone to fend off the Titans until the tower begins to collapse. Climbing the tower, Ymir tells the other recruits to grab onto her Titan, which protects the others from falling to their deaths. When the tower is reduced to rubble, Ymir continues to fight the Titans but she is soon outnumbered, and the horde eats away at her Titan until the Scout Regiment arrives to finish them all off. Ymir is extracted from her Titan, missing some limbs and with serious abdominal injuries, and Christa tells Ymir her true name "Historia" before Ymir falls unconscious.