Board Thread:Theories and Speculation/@comment-3314412-20141104213636/@comment-25382671-20141105004551

Salamancc wrote: Zetsu's ability isn't classified as a Dojutsu and Ranmaru is a non-canon character. Ranmaru, that's his name.

I believe he is "non-canon" up to a point, since he is part of the Anime fillers... fillers like those are loosely based on or out of some "canon" concept, so it's probably correct to assume that, even though Ranmaru doesn't exist, someone else with some sort of Doujutsu (aside from the "Great Three" [reference to existing Minor Doujutsu]) exists.