It a world were there is demons and upper moons and demon slayers and hashiras and the demon slayer need to kill demons and the king demon name muzan,and the master of the hashiras name is kagaya,in the hashiras ther is giyuu the water breathing,Rengoku flame breathing,mitsuri love breathing,muichiro mist breathing,Obanai serpent breathing,sanemi wind breathing,uzui sound breathing,Gyomei stone breathing,Shinobu butterfly,the upper Moons Duma and kokushibo and akaza,sanemi have a brother ganya