After the death of the Flame Pillar, Rangoku. Tanjiro is dead set on making sure his family is okay, especially you as you were his successor to become the next Pillar. He also wanted to see if any of his family members had any information about other fire related breathing styles, to his surprise his father and younger brother weren’t help as his father was a drunk and destroyed the book. Y/N was the only person with the answers but it felt too soon to push for them. He hasn’t seen you since that mission and he remembers the words your brother said to him, a promise to take care of you.