Board Thread:Theories & Speculation/@comment-1512913-20141028151348/@comment-4912646-20141031183209

ItachiWasAHero wrote: It IS proof that all Genjutsu is Yin release, BeyondRed.. some Genjutsu are ALSO different natures added to it too, such as Cii's Lightning release Genjutsu.

We've essentially known that ever since Second Mizukage told us, but as of now only his Mirage Genjutsu is listed under Yin Release. I think C's technique was part of the problem, since it was the first example of a technique being two natures at once (which we now know is possible.