In feudal Japan, different clans are waging wars against each other. All of a sudden, demons spawn around the country and add to the chaos. In Ikusa Gami, the player takes control of Inugami, the embodiment of the god of war, to cleanse the lands of the demons.

This title is a 3rd person hack and slay action game. Inugami can use a combination of various attacks to get rid of the demon hordes, of which there are plenty in Demon Chaos. In most missions, there are friendly armies fighting along side the protagonist that have to be protected. The player can give the armies a rudimentary follow command and create various pillars, which can for example heal surrounding units. Inugami's health can be restored by getting close to Aoi Yasaka, a priestess that accompanies him throughout the player's journey. During the fight, a spirit gauge can be charged to unleash special attacks - enemies occasionally drop items to restore the spirit energy. After each mission, new weapons are unlocked with gradually improving properties.