you had just become a new hashira and Kagaya sent you on a small mission to meet you co-workers that you will be working with in the future, you had already met Obanai, Giyu, Sanemi, Gyomei, Tengen, Shinobu, and Mitsuri, you heard about a hashira named Rengoku, but he had supposedly died, unable to live and tell the story of fighting an upper rank demon, specifically upper three...the only hashira you hadn't met is mist hashira, muichiro tokito...you arrived at his estate, and went to go knock on his door when you heard a voice from behind you...

Muichiro-"what are you doing at my estate, peasant..."

it was muichiro, he was sitting on a well, drinking water...

[this is before swordsmith village ark, and after mugen train ark, so tanjiro is still in a coma]