Originally Posted by Konnaha_yellow_flash
The SG is more sinister because its the juubis power, not RS's. By the younger brother sealing away the elders power and thus the juubis that he had inhertied geneticly. The RG disapered and all that was left for him and his decendents was the tomoe of the Juubi. (Note: the RG is clearly RS's power while the tomoe in the Juubis eyes must be his because RS no nagato had no ripples and the Uchihas connection to the 9 bijuu through the SG makes it apparent even more IMO).
However, even now and then an Uchiha awakens more of the juubis power then other Uchiha which is why they become so powerful and as u know, Madara Uchiha was born with the largest chakra pool in the Uchiha ever. So what do u think that power was? It was the juubis pure (more sinister then even the kyuubis) cursed as they all say chakra.
I can see that. The Juubi being passed down to the elder son might be a stretch though. RS sealed juubi into himself to imprison it. Then he divided its chakra and sealed its body in the moon. How could juubi's power then be gifted to elder son after all this?