Board Thread:Theories and Speculation/@comment-28939725-20161201164545/@comment-25122992-20161201165109

Since Nagato never used it, despite the fact it'd be pretty useful in some situations, I'd say he never managed to master it. Nothing implies he ever got to know that his Rinnegan is in fact Madara's evolved EMS, also it's likely that he never knew about Susanoo as a technique as well. He couldn't even use Limbo which is already a Rinnegan techique, yet only Madara proved to be able to use it.