Boss Renoma is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here.
In the near-future city of “Tokyo,” the boss of the slum district No. 2 gang, Double Dragon Cross, Renoma, has been captured. “The defendant, Sasaki Renoma, is sentenced to 28 years in prison at the Paradiso Island maximum security prison.” Rise from the lowest depths of the worst prison and survive!! The side story of “Prisoner Riku” begins!!