Demon Slayer is undoubtedly the most popular anime of the new generation, and Ufotable certainly deserves credit for the ...

Demon Slayer tells the story of Sun Breathing, the first and strongest technique that shaped Tanjiro’s path and all other breathing styles.

and it is a result of Tanjiro’s ancestors learning the Sun Breathing techniques. This puts Tanjiro on Muzan’s radar in the series but should have also sparked Kokushibo to seek him out.