Fort of Apocalypse

Overview

Yoshiaki Maeda has been falsely accused and detained, along with delinquents from all over the Kanto region, in the juvenile correctional facility, Shouran Institute. Yoshiaki is as typical as a boy can get, so when he finds himself living in this violence-ridden prison, he can’t think of anything worse. His cellmates, Iwakura, Yamanoi, and Yoshioka, are a cunning crew and soon Yoshiaki finds himself pulled into a feud going on in the prison. Then suddenly, a prison van crashes into the facility and what shambles out of the wreckage are flesh-eating zombies … and so the curtain is raised on this bone-chilling story of panic and horror … (Source: Kodansha USA)

Source: AniList