平将門
The clan was based in Kanagawa Prefecture, specializing in horseback guerrilla warfare and naval espionage. According to some sources, the family has roots in the 10th century when they served Taira no Masakado in his revolt against the Kyoto government. The use of the name started with the first leader ("jonin") of the clan: originally surnamed "風間" (Fūma), with a different kanji, it was later changed to homophone 風魔. Each subsequent leader of the school adopted the same name as its founder, making it difficult to identify them individually. This school was in the service of the Hōjō clan of Odawara.