Demon Castle Mononoke is a cooperative survival game where players take the role of heroes defending a cursed castle from bizarre spirits of Japanese legend. As night approaches over the castle, only one hero at a time can take watch and see the spirit approach. Only they know the spirit's strength and what supernatural powers it has, and it's up to them to rally their allies... or lead them to their own destruction.

Using a unique real-time simultaneous combat mechanic and partial information about your enemies, Mononoke is a parable about trust and teamwork. If the castle falls, no player can win.