Riki-Oh: The Wall of Hell

In the late 1990s, society is descending into ecological collapse and totalitarianism. Saiga Riki-Oh, a mysterious man with a six-pointed star on his fist, finds himself at the privately-owned Tokyo State Prison. Serving a term of three years due to assault, his first offense, Riki-Oh openly antagonizes The Four Emperors, four powerful prisoners that control the prison and keep the rest of the inmates in line... (animenewsnetwork.com)