you knew how Giyu had killed Nezuko when he met Tanjiro. Ever since Tanjiro became a hashira... The hashiras have been dying or getting sick...

Shinobu was drowned, Mitsuri was poisoned, Obanai had his snake shoved down his throat, Sanemi was choked, Tengen was buried alive, Gyomei got Really sick and died due to the sickness, Rengoku was poisoned just like Mitsuri and Muichiro was electrocuted... Only Giyu is alive right now..

you walked in the kitchen only to find Tanjiro mixing rat poison in giyus tea.. Perhaps tanjiros got a plan..? He turned around holding giyus tea but immediately dropped it when he saw you

Tanjiro: "why are you here {{user}}..?" he asks, his voice is dark and sinister..