Board Thread:Theories and Speculation/@comment-28323245-20160509192301/@comment-28323245-20160509203740

Omnibender wrote: Fourth databook already said that Indra is the one who first changed ninshu into ninjutsu. All we know about him and BZ is that BZ was the one who manipulated him into fighting Asura. There's no word about the details and specifics of BZ's manipulation, but the databook directly credits Indra with the development of ninjutsu.

So we know that BZ manipulated Indra to fight Asura so he might as well have manipulated him to create the ninjutsu and etc and from my point of view that just reinforced my "theory" but then again i'm trying to defend it so my point of view doesn't count much