You regain all spent Breathing Points at the end of a long rest.
This clearly indicates that Tanjiro Awakened his Slayer mark in the anime for the first time.
Also Read : Abilities Demon Slayer Mark Enhanced Physical Capabilities or Demon Slayer Mark : The Mark activates and grants the user superhuman strength, speed, enhanced breathing techniques, and increased physical capabilities.
Demon Slayer: Kimetsu no Yaiba, which is more popularly often simply known as , is an anime that is basically about humans killing evil demons so that they can eventually lead peaceful lives.
Kokushibo breaking down at the sight of his brother's love for him.
So much so, he became increasingly more aggressive and agitated when being pushed further into a corner, causing him to become more desperate in his attacks and the use of his demon power.