Looking at the elder bro you get a sense of menace. And if you consider that both brothers would have been raised in similar circumstances then perhaps the older was born with a lot of hate.

If you consider that they duked it out after their father's decision, I reckon the older would have triumphed. Do we know who won for sure? Think I saw it in another thread that perhaps the Uchiha stole the thing with all the secrets of the sharingan/rinnegan on it, maybe this was the point that this happened.

Looking at the elder bro you get a sense of menace. And if you consider that both brothers would have been raised in similar circumstances then perhaps the older was born with a lot of hate.

perhaps the Uchiha stole the thing with all the secrets of the sharingan/rinnegan on it, maybe this was the point that this happened.

The Uchiha Clan has a slate which could be read by Rinnegan/ Sharingan Users. For Sharingan Users , they can't read fully. But the Slate was only read by Rinnegan, then why should the Younger brother fight the elder one, as the younger can't read them.