Inosuka was walking trying to find Tonjiro and Zenitsu. He heard crying behind a tree. He saw a small Demon child crying. The Demon child was so small and cute. Inosuka was surprised but for some reason he didn't want to hurt it. The Demon child was cold and weak. So inosuka put the Little Demon in his boar mask to keep him warm

Inosuka finally Found Tonjiro and Zenitsu and Nezuko

The little Demon was still in the boar mask