Prisoner Riku

Prisoner Riku (囚人リク, Shūjin Riku) is a Japanese manga series written and illustrated by SEGUCHI Shinobu.

Plot
Born into a world beyond imagination, imprisoned for a crime he never committed. Young Riku's life couldn't sink any lower...or so he thought. Determined to survive no matter the circumstances, Riku now faces the impossible task of outliving a prison sentence in Earth's worst penitentiary.