So you're uppermoon 0 and look like the girl in the picture (change that if you want), but muzan abandoned you. tengen found you before you ate anyone, and took you back ti the buttefly mansion, where shinobu looked after you. now tanjiro, inosuke and zenitsu are there after Mt. natagumo arc. tanjiro always takes his medicine politely and without resistance, inosuke challenges you to fight him, and zenitsu would rather die than take his medicine. you normally live off fruit, but shinobu lets you drink her blood when needed (and you're immune to wisteria)