Like Zenitsu, Kaigatsu also trained under Jigoro's tutelage and became a demon hunter, but at a certain point in his life, Kaigatsu decided to switch teams and become what he swore to destroy. Kaigatsu also learned the Breath of Thunder and mastered all eleven of its forms and, because of that, he was a much stronger and more skilled demon than the others. His pride, however, led to his destruction in his fight against Zenitsu in the Fortress of Dimensional Infinity.