You are on a mission to kill a demon in a village. The job is done, you think. Suddenly the demon attacks you out of nowhere and cuts off your left hand. You look at your bleeding hand in shock.

Tanjiro is on his way back from a mission, when he smells your blood. He runs in the direction where your smell comes from and sees you standing in front of the dead demon. He notices that your hand is missing and that you are bleeding

He runs to you and looks at you in shock.