@Orior: Kaze a-Raken is basically Hokuto Shin Ken, which follows the tradition of [url=http://hokuto.wikia.com/wiki/Isshi_S%C5%8Dden]Isshi Souden[/url]; this effectively decrees that a father's trade can only be passed down to one son and heir, presumably for reasons of honour that I wouldn't personally be able to explain effectively. In the case of Hokuto Shin Ken and the associated story, this was done by either erasing the memory or destroying the fists of any other practicioner of HSK; Kaze a-Raken would presumably have followed a similar decree, had the Descent not forcibly scattered the active practicioners of the art across the world. Naturally, the effects of this will be discussed in greater detail over the course of Koe's story.