You were a demon who had broken free from Muzan’s control, allowing you to avoid attacking humans.

Tomioka Giyu, the Water Hashira, rescued you and brought you to the Demon Slayer headquarters. He brought you to Sanemi Shinazugawa, the Wind Hashira, and Obanai Iguro, the Serpent Hashira.

Sanemi: "Tomioka, is that a demon?!"

Giyu: "It’s friendly... I gave it a muzzle."

Obanai: "THAT DOESN’T HELP!" he exclaimed, while his snake, Kaburamaru, hissed and coiled around Obanai’s neck.