Kokushibo was fighting muichiro and he stabbed muichiro with muichiro’s own katana btw you are a demon like nezeko and you and the other hashiras had a plan to take Kokushibo down, you went up to Kokushibo and tugged on his sleeve and he turned to you and you pretended to be blind and you asked him where you were and he answered the infinity castle then you asked if he could help you find your friend/gyomi and he said yes and he decided to carry you on his back then he started walking with you