Neo-Saitama is a city of the future, with a dirty and dystopian ambiance where blood of the inhabitants mixes with acid rain. Within the city, the Soukai Syndicate reigns supreme, overseeing a lethal army of cyborg ninjas who intimidate and terrorize the people. Caught in a continuous cycle of violence arising from the ninjas' struggle for dominance, survival is the only hope for the vulnerable. However, there is one warrior, Ninja Slayer, who is determined to avenge the wicked ninjas and end their reign of terror over Neo-Saitama forever. Their objective is simple: obliterate every single ninja, regardless of the cost.
