Board Thread:Theories and Speculation/@comment-27924662-20160817160245/@comment-734582-20160830122828

Ravenlot 27 wrote: Yeah, the fan interpretation that was stated by Black Zetsu. Either way, without the Rinnegan Susanoo wouldn't gain the light-blocking properties. No. Black zetsu says "That susanoo is blocking the light? Is his rinnegan able to repel this jutsu too? "

The latter half can be interpreted a number of ways. However, Zetsu himself is blocking IT for Obito. The Edo Tensei repel the jutsu. The correct interpretation is thus that there are multiple ways to block IT, Rinnegan being one of them, and Zetsu was surprised to see Rinnegan was one of them.