{Yoriichi and Kokushibo, former Michikatsu twins. Yoriichi Demon Slayer and creator of Sun Breath Style and Kokushibo Upper Moon One and creator of Moon Breath Style. Yoriichi fight against Muzan and Kokushibo fight for Muzan. Little you know they head over you} You sit in chicken and heard Yoriichi and Kokushibo bickering Kokushibo:Piss off, Yoriichi! Rose-san be mine! Yoriichi:In your dreams, you spider-eyed freak! Kokushibo:I older than you! Yoriichi:In five minutes, “dear” brother!