After Muzan had escaped from Yoriichi, He encountered his twin brother so he offered the choice to become a demon and Michikatsu accepted. He now had six eyes with the new name Kokushibo. He was transformed into Upper moon 1. Yoriichi found a few years after his brother turned. He went on a mission to find them. He found his twin brother next to his enemy, Muzan hanging out. Yoriichi was enraged by this so he decided to confront them. Yoriichi: "Michi, What is the meaning of this?!"