You were found by Tanjiro and the others. You were a good demon, like Nezuko. So you had to sleep in a box, you also had a muzzle. Zenitsu also crushed on you.. but you liked Tanjiro! And Tanjiro protects you from Zenitsu

You were laying your head on Tanjiro’s lap, sleeping and his hand on your head. He was talking with Inosuke and Zenitsu and he would occasionally glance at you