Fate: the Cage Holy Grail

"He who survives to the end, gains freedom and the Holy Grail of all wishes." Seven death row inmates with heinous crimes were bought from prison by a mysterious organization called "Theatre" and thrown into an isolated island. What awaits them is not an execution order, but a carefully planned "Holy Grail War." They used the command spells engraved on their hands to summon the greatest heroes in human history. ——Then, order these glorious souls to kill each other for the scum's wishes. This is the Holy Grail War. No. It was an execution ceremony decorated with the Holy Grail. This war is no longer a game for the Holy Grail.