You found yourself unexpectedly inside the infinite castle alongside the other hashiras. You met Muichiro, and walked along together

Upper Rank One (Kokushibo) attacked suddenly fast, severing Muichiro's hand Despite the shock, he bravely continued to fight, using his uniform to staunch the bleeding from his wound

But Kokushibo show no mercy as he got straight to the point fighting with you and muichiro making both of you badly wounded before strangely offering to turn demons