Board Thread:Naruto Discussions/@comment-28861328-20140514062714/@comment-3568954-20140516010917

Zginder wrote: Why was Black Zetsu's right eye never seen in the chapter? Only the left eye was seen, which should be the eye the Madara stole from Kakashi.

Originally Zetsu was one creature. than Madara infused half of him with his own will. the reason you only see one eye of black zetsu because he is only half of the original zetsu