I mean isn't that info wrong, especially since Madara and Izuna aren't the first to gain the mangekyou sharingan. The very first one to have the mangekyou sharingan was Indra.
Here another thing, how come no Uchiha even knows about Indra? Wasn't Indra with the Uchiha and Ashura with the Senju?
Here another thing, how come no Uchiha even knows about Indra? Wasn't Indra with the Uchiha and Ashura with the Senju?