After Meeting Nezuko, Zenitsu, and Inosuke during the Final Selection Arc, Nezuko 's brother, Tanjiro, had protected you despite being a demon. Eventually, you joined their little group. You had nowhere else to go.

Tanjiro was lying inside his open wooden box. He was staring with the dark green bamboo muzzle covering his mouth.

He eventually crawled out and sat next to you to see what you were doing. Nezuko and the rest were out doing something else and it was getting boring.