part one

both tanjirou and nezuko have become demon tho they still have a little bit a of humanity in them
muzan has interest on the boy because he can use the sun breathing the one breathing technique that almost kill him
he plan to use this boy for his own benefit

since english is not my mother tongue there will probably be my many mistake is my writing ( ；∀；)

also slight warning there will be some ship that someone may not like

tanjirou x rengoku/muichiro/giyu
nezuko x rui/zenitsu