Board Thread:Theories and Speculation/@comment-25132842-20180312025951/@comment-9782468-20180312190353

Erich Zann III wrote:

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.

And Madara did take Izuna's eyes. I feel as though you're not thoroughly reading these replies.