Satsuriku no Queen Dead: Nananin no Onna Shikeishuu

Overview

Death row inmates– Those who have committed heinous crimes and have been sentenced to death by the law. A woman, Akari is on her way to "Deep Palace," a death-row prison island where these inmates are held, with a mysterious purpose. She thought she could successfully complete her mission, but to her surprise, the condemned prisoners have started killing each other! They were divided into male and female teams, and a battle royale called the "Killing" was being held, where the winning team could escape! Can Akari survive the "Killing" and escape from the prison? A prison battle royale featuring blood, eroticism, and bad guys, where all the characters are scum!!!!! (Source: Takeshobo, translated)

Source: AniList