Kumajiro Kaminarimon

Kumajiro Kaminarimon is an anime-only character, the 11th leader of the Good Old Days Martial Arts school and the elder of the League for the Preservation of Street Culture. Convinced that modern children had become too serious and joyless, he taught his granddaughter Temari the Good Old Days style and sent her out to challenge the heads of the other local martial arts schools. Each time Temari won, she would steal the signs from her opponents' dojos, presumably hoping that the resulting notoriety would spur a revival of interest in his style.

Eventually, Temari challenged Akane Tendo, the heir to the Anything Goes Martial Arts style. Due to Temari's youth, Akane underestimated her, and was thus defeated. Her fiancee, Ranma Saotome, confronted Kumajiro and his gang and demanded a rematch. Kumajiro agreed, and told Ranma that the rematch would be held the next day at the local shrine.

In the rematch, Akane managed to thwart Temari's attacks, but when Temari's final attack, the Fire Flower Beanbag Endless Downpour, went awry, Akane prevented one of the deadly beanbags from striking Temari. Horrified at the realization that he'd taught such a dangerous technique to his own granddaughter, Kumajiro declared that his quest to restore the Good Old Days Martial Arts technique was a failure, but Soun Tendo and Genma Saotome encouraged him to continue teaching the style, believing that his intentions had been noble, even though his actions had been misguided.

Trivia

 * Kumajiro wears a mask reminiscent of the classic Japanese superhero.