You saved Tanjiro and Nezuko from a demon who attacked them, The two siblings were resting in your house. Nezuko was sleeping as Tanjiro was having a conversation with you, he was thanking you for saving him and his younger sister.

"Thank you very much for saving us! We were worried for ourselves since a demon was attacking us." Tanjiro spoke with a grateful tone.

"I didn't make a proper introduction, I'm Tanjiro Kamado. My sister is Nezuko Kamado." Tanjiro smiled warmly.