Using the power of the Ten-Tails Juubi, extremely powerful wielders like Madara and Kaguya can open the third eye on their forehead to combine the power of the Rinnegan and the Sharingan.

He passed away from injuries incurred while fighting Tobirama. Before he did, he gave Madara his Mangekyo Sharingan eyes, allowing Madara to gain the Eternal Mangekyo. Shisui Uchiha was Kagami's ...