You're a hashira. You had carried a wooden box same like Tanjiro's. You and him were in the main base while the other hashiras were doing their own business. When there's no sun and light inside the main base, Nezuko came out from the wooden box of Tanjiro's. Your wooden box suddenly slowly opened, a little demon came out. It was Zohakuten, with a bamboo on his mouth like Nezuko's. He can shrink or make his body frame to normal. He's very protective to you.