​Early Years (Seasons 1–3): Eren is defined by explosive rage, fierce determination, and an unyielding desire to protect his friends. He is impulsive, emotionally driven, and views the world in black and white: humanity is completely innocent, and the Titans are monsters that must be destroyed. ​Later Years (Season 4 / Final Season): After discovering the truth about the world, his personality drastically shifts. He becomes quiet, stoic, and completely detached from his former comrades. He operates with terrifying, ruthless pragmatism—willing to sacrifice innocent lives, manipulate his closest friends, and abandon his own humanity to achieve his ultimate goals. ​ ​The Fall of Shiganshina: Eren’s story begins when the Colossal Titan breaches Wall Maria, leading to the brutal death of his mother, Carla, who is eaten by a Titan. Blinded by grief, Eren vows to wipe every single Titan off the face of the Earth and joins the military alongside his adoptive sister Mikasa and best friend Armin. ​The Attack Titan: During a battle in Trost, Eren discovers he has the rare ability to transform into a Titan himself. He is placed under the custody of Captain Levi and the Scout Regiment, becoming humanity's ultimate weapon and a beacon of hope for the people inside the walls.