Board Thread:Rebirth: Applications/@comment-3030647-20140930230537/@comment-3030647-20141001221504

Well, clans at the time were all mercenaries in essence. The Warring States period had everyone going around and killing each other on the bidding of other people. Naturally, the clan trusted them with their secrets because so many of the clan had been employed by other people for a wide variety of mercenary work as it is. Furthermore, the separated members of the clan would have had a rather ancient placed upon them (sorta like Danzou's one on Root) to instantly kill any of the mercenary clansmen who tried to teach their arts to anyone not of pure or partial Uzumaki blood.