|I don't believe it. For the first time in human history... I communicated with a Titan.|
|— Ilse as she writes in her notebook.|
Ilse Langnar (イルゼ・ラングナー Iruze Rangunā?) was a member of the Scout Regiment. She was a participant of the 34th expedition beyond the Walls and was in charge of the left wing of the second brigade. In a notebook, she documented information regarding a talking Titan she encountered, which later aided Hange Zoë's research.
Ilse was noted to have resembled Ymir in appearance. She had short black hair that was parted to the right side, lightly tanned skin, and gold-colored eyes with a small patch of freckles below each one. She wore the standard Scout Regiment uniform and cape with a gray shirt underneath.
Ilse appeared to be quite emotional, yet brave, attempting to stand firm in moments of despair. She seemed to be a very devoted and smart soldier. As seen during her last moments, she cared deeply for her family, regretful of being unable to give anything back to her parents. Ilse thought of herself as a proud member of the Scout Regiment and resolved to do whatever she could to benefit the branch. Though she took what time she could to document information about the talking Titan, she ultimately lost her composure upon bringing up the subject of Titans eating humans, screaming at the cowering Titan before running away in fear.
During the 34th expedition outside the Walls, Ilse's entire flank is massacred, with her being the sole survivor. With her horse lost and omni-directional mobility gear broken, she abandons her equipment and flees afoot north to a nearby forest, searching for a route to the Walls. Knowing her chances of survival are slim to none, she takes out a notebook and begins documenting her experiences, hoping her notes at least prove useful to humanity in the future.
After profuse running, she inadvertently runs into a Titan, which chases and corners her against a tree. However, instead of immediately eating Ilse, the Titan hesitates, causing her to question if it is an abnormal. It then shockingly begins talking, saying "a subject of Ymir" and "Lady Ymir... Well met," while bowing in seeming reverence.
Ilse is left thoroughly confused by the Titan's ability to speak, and questions it about the nature of Titans and their origin, writing every question and the Titan's reactions in her notebook. However, the Titan does not respond, and instead moans in increasing frustration. Ilse angrily yells at it, asking why Titans eat humans and what their objective is — calling them useless lumps of flesh that should disappear from the world. The agitated then Titan begins tearing off its cheeks and gushing blood before her.
Horrified, Ilse attempts to flee, but is quickly caught by the Titan. As the Titan prepares to devour her, she hurriedly continues writing of the situation in her notebook, until the Titan bites off her head. After killing Ilse, rather than eat her, the Titan leaves her body inside a tree.
One year later, the Titan that killed Ilse attempts to kill Hange Zoë before returning to the tree Ilse's body is hidden in. After it is killed by Levi, Ilse's body and notebook are found and recovered.