<P> The Attack on Titan manga and anime series feature an extensive cast of fictional characters created by Hajime Isayama . The story is set in a world where humanity lives in cities surrounded by enormous walls; a defense against the Titans, gigantic humanoids that eat humans seemingly without reason . The story initially centers on Eren Yeager with his childhood friends Mikasa Ackerman and Armin Arlert, who join the military to fight the Titans after their home town is invaded and Eren's mother is eaten . They are part of the 104th Training Corps, whose graduates assume different positions in the Military, including the Garrison Regiment, the Survey Corps and the Military Police Brigade . </P> <Dl> <Dt> Eren Yeager (エレン ・ イェーガー, Eren Yēgā, alt . "Eren Jaeger") </Dt> </Dl>

Who's the main character in attack on titan