Eren is a minor protagonist from the series Attack on Titan. He is an Eldian who is capable of becoming a large humanoid called a titan. He served as an Eldian spy among the Marleyan military for information and founded the Eldian Restorationists who seek to bring prosperity to their race. Throughout his time as a spy he had obtained a titan power that being the Attack titan which was kept from Marley's possession for generations as it would later be passed down to a fellow restorationist, Grisha.

He is a middle aged man with notably older features likely due to the length of time he had his titan power. He still retains short brown hair and gray eyes. His titan appears to be 15 meters with a muscular build and keeps his human features like the hair and eyes.

As a shifter he can transform to and from titan form at will. While his titan doesn't have unique physical powers it can however give the user glimpses into memories of its future inheritors which influence the holder's actions. He also possesses a form of regeneration as a shifter.