She is Eren's adopted sister who watches over Eren after Eren's mother was eaten alive by a Titan.
When she and her family were ambushed by slave traders, she gives up after seeing her father and mother killed right in front of her eyes. Unable to move, Eren arrived and killed two of the slave traders. When the third slave trader overwhelmed Eren and started to choke Eren to death, Eren urged Mikasa to fight and to survive. Mikasa grasped the knife and plunged into the slave trader's back. The two were found by Grisha Jaeger and the others who are stunned by how the two killed the slave traders. Eren and Grisha accepted Mikasa into their family.
The numbers "844" that her mother had embroidered on Mikasa's arm represents the year of the setting.
Mikasa Ackerman is created by Hajime Isayama.
A master of all subjects, and widely considered one of the best in our history.
— Keith Shadis (Episode 4)
She is young, beautiful woman who has fair skin, black eyes, and black hair. Five years after the Shiganshina District event, she has grown her hair past her neck and shoulders until Eren tells her to cut it short because it would get tangled by the 3D Maneuver Gear. Her past self wears a thick scar that covers her mouth occasionally.
She is a happy and carefree girl until some slave traders killed her parents. After Eren had told her to fight and to survive, Mikasa loses her innocence and kills the man who was choking Eren. Mikasa adopts Eren's survival dogma and when Eren refuses to eat the bread, Mikasa knocks out Eren and reminds him to survive. She has matured into a serious and intelligent person.