Webwho would win if tanjiro and kokushibo fought? Let's delve into a thorough analysis of their ultimate showdown in demon slayer, examining their strengths and. Webtanjiro becomes a demon in chapter 201 of the demon slayer manga after his battle with muzan. Becoming a demon is relatively easy in the series, with muzan. Webtanjiro's transformation into the demon king showcases the internal battle of good versus evil & redemption. The change affects tanjiro's relationships with loved.