Nyudou Mifune
His strange tasks are not in vain though - the eliminated middle schoolers realized their improved techniques (Ryoma and Kintarō can hit 5 balls, Kenya has better balance and improved speed, Sakata can run in zig zags, Gakuto can do a low moonsault, Sanada has a larger and stronger black aura, Kei lost weight, etc.)
Two years prior to the storyline, it is unknown when, but during this time, Byōdōin Hōō went to train in the Mountains with the Drunken Coach.
One year prior to the storyline, it is unknown when, but during this time, Tokugawa Kazuya went to train in the Mountains with the Drunken Coach.