Board Thread:Theories and Speculation/@comment-25132842-20180312025951/@comment-25132842-20180312164907

E.g. Shisui killed himself to give Itachi MS, Itachi died to give Sasuke MS, and EMS was unknown till Madara got it so it's not like Madara could've just switch eyes with Izuna. Well he could, he just didn't know it would've solved their problems much easier.

Indra Otsutsuki had the Mangekyo Sharingan. It was not unknown. Madara and Izuna were just the first Uchiha to unlock it. Hagoromo also had the Mangekyo. So Hagoromo was the first to activate the Mangekyo. But he mostly used his Rinnegan, so his eyes never took that much damage.