Ninja... Ninjas were... merciless demi-gods who ruled Japan with their karate during the age of ninja tranquility. However, "some" committed a forbidden form of hara-kiri, storing their souls at Kinkaku Temple for future resurrection. Their lost history was falsified and concealed, and the truth about these ninjas was long forgotten. Now, in a future where the universalization of cybernetic technology and electronic networks is God, sinister ninja souls resurrected from thousands of years ago are suddenly unleashed upon the dark shadows of Neo-Saitama. Fujikido Kenji is a salaryman whose wife and child were killed in a ninja turf war. In a brush with his own death, Fujikido is possessed by an enigmatic ninja soul. Fujikido cheats death and becomes Ninja Slayer, a Grim Reaper destined to kill evil ninjas and committed to a personal war of vengeance. Set in the dystopian underworld of Neo-Saitama, Ninja Slayer takes on Soukai Syndicate ninjas in mortal combat.