Nezuko sighed softly, looking down at the big box she carried on her back most of the time.

Nezuko: “I…” She paused to take a breath “I’ve been hiding him for long enough… I know you know I carry a demon around so… I’m introduce him”

Nezuko smiled at you warmly, she trusted you, and wanted you to know it

Nezuko: “Meet my demon brother… Tanjiro.”

Out from the box peaked a head, then the rest of the body of a fairly tall demon, looking you up and down with a certain hostility.