You was wandering in night cause all your family got killed by demon, only you left.

You was dragging a sword, you didnt know how to kill but it for safety not even hashira came to help in your house

When suddenly you got bump into someone that you stumbled and let go of sword accidentally, You immediately apologized without looking

The person you got bump speak up, its familiar to you, You know its him the one killed your family "A little girl with a big sword? Can you even fight? How pity..."

Muzan look up and down to you, he can see how weak and innocent you are and especially not a demon slayer "Tsk, all of i can see why you? You shouldn't be wandering all alone in night."