Eren Jaeger (エレン・イェーガー Eren Yēgā) is a member of the Scout Regiment and the main protagonist of Attack on Titan. He is the only son of Grisha and Carla Jaeger, the adoptive brother of Mikasa Ackermann, and possesses the power to transform into a Titan.

He was born and raised in the Shiganshina District located on the southern edge of Wall Maria. He lived there until the year 845, when the Colossal and Armored Titans breached the Wall, allowing a flood of Titans to invade and destroy the city. During the incident, Eren witnessed his mother being murdered and eaten by a smiling Titan. This event aroused in Eren an intense hatred towards the Titans, and he swore to wipe all of them off the face of the earth.

Two years later, he along with Mikasa Ackermann and his best friend Armin Arlelt joined the 104th Cadet Corps. The three successfully graduated, with Eren ranking as the 5th best cadet, and they joined the Scout Regiment following the struggle for Trost.mpass Historia Reiss, squad leader Levi, Eren's father Grisha, and other supporting characters.

Mikasa Ackermann (ミカサ・アッカーマン Mikasa Akkāman?) is the adoptive sister of Eren Jaeger, and is the main female protagonist of the series.

After her biological parents were murdered by human traffickers, she was rescued by Eren and lived with him and his mother and father for approximately a year before the Fall of Wall Maria.

Though she desires only to live a peaceful life with Eren, Mikasa chose to follow him into the military — where she is considered the best soldier among the 104th Cadet Corps. She later joined the Scout Regiment to continue following and protecting Eren. 

 Armin Arlelt (アルミン・アルレルト Arumin Arureruto) is a soldier in the Scout Regiment. He is also a childhood friend of Eren Jaeger and Mikasa Ackermann, and is one of the two deuteragonists of the series.

  Although he appears to be the physically weakest of the 104th Cadet Corps, his high intelligence and strategic genius makes him an invaluable asset, though he does not consider himself to be one and is known to have a low self-esteem.