Specially drawn manga by Natsuki Hokami in Official study book of "Demon Slayer: Kimetsu no Yaiba" and "Kimetsu Gakuen!" "Total Focus Drill" is a learning book series in which nine of the highest-ranking swordsmen, the "pillars" of the Demon Slayer Corps, teach you about your own breathing! By all means, you should get your hands on a book that you can enjoy learning with "full concentration" from children to adults!