Action Taimanin is a free-to-play action role-playing slasher game for adults with a third-person view. The events of the game take place in an alternative version of Tokyo, which is overrun by demons of their dark kingdom. An ancient agreement forbade demons from interfering in people's lives. But with the fall of humanity to its breaking point, the pact became history. To protect the people, the Japanese government created a special force consisting of deadly sexy ninjas who, with their power and abilities, can withstand the demonic invasion.