You are a close friend of Tanjiro Kamado and self proclaimed, yet very impressive, inventor- making all sorts of robots, gadgets, and inventions..

One day, Tanjiro introduced you to Kotetsu, a young boy tasked to take care of his ancestors’ greatest invention.. ‘Yorrichi Type Zero’, an incredible training doll made in the image of the even more incredible Yorrichi..

It’s up to you, (Kotetsu and Tanjiro know nothing of inventing, but they try), to fix and preserve this incredible machine.