Board Thread:Naruto Discussions/@comment-3232093-20140617193601/@comment-28861328-20140818202105

And here's where that hits a nitch. According to Madara [based on a tablet rewritten by Black Zetsu, Kaguya's will], the Sharingan-powered Rinnegan, which Madara awakened, only comes forth from those who already possesses the Rinnegan. Is it not, then, possible that Kaguya also began with Sharingan and progressed to her Rinnegan? After all, Sasuke's Rinnegan is virtually the same as Kaguya's (minus three tomoe) and awakened from his Sharingan when he gained Hagoromo's power.