Board Thread:Theories and Speculation/@comment-27082825-20150116155842/@comment-26023629-20150122173400

Well, the only other possibility under that theory is fire+wind+water (barring the existence of the two unknown two- part natures), which involves natures from the Land of Water, and with the heavy persecution of the Yukis (and presumably individuals with boil release) as well as the requirement of scorch release, which only can be found in the Land of Wind as far as we know, no one else could do it. As to how Mu cam up with the idea: Mu's clan probably just tried breeding as many advanced nature users as they could find. Since the only other advanced nature available in the area is explosion release, Mu possessing dust release occurred simply because there were only so many possibilities. From knowing his own ancestry, Mu was able to figure out how it worked and reproduce it in Onoki.