Nanbaka

Nanbaka (ナンバカ, Nanbaka) is a manga written and illustrated by Shō Futamata.

Plot
Four young men are assigned to Nanba, the world's most formidable prison. Jyugo, who attempted to break out of prison and ended up extending his jail time; Uno, who likes gambling and women; Rock, who likes eating and fighting; and Nico the ex drug addict who likes anime. The action follows the daily lives of the prison’s inmates and guards.