Chronicles Of Carnage (Volume 1)

Kazuki "William" Muldoon was a typical high school student who has a secret, he has a dark alter-ego inside of him known only as "Bloody Billy" but one day after a group of delinquents decided to try to pick on Kazuki because of him being only half Japanese and half Irish-American, they took his favorite book "Lord of the Flies" this was a mistake made by the delinquents when they decided to pick a fight with the wrong kid. That's when Bloody Billy comes out and goes on a murderous rampage. After changing back, the police chase after Kazuki and he gets summoned by a shinigami sponsor by the name of "Mephisto" who offers our hero a chance to compete in a battle royale tournament that his Marine Corps father competed in. But the only thing standing in his way is 99 other combatants and a crown prince who wishes to rule over the empire.