In the manga the prophecy of brothers (and rivalry) made them stronger for centuries. But did it really start with only Hagaromo's children?
Inside of Naruto's mind, Hagaromo had explained the birth of both him and his brother. Where his mother, Kaguya, blessed him with all her powers and the rinnegan and passed down the Byakugan to Hamura. The strength of the Jyubbi was sealed in him giving him even more powers. Decades later Hamura is somehow on the moon and before death awakens a powerful eye that can rival the Rinnegan and the Rikudo's Sennin powers.
Two things that come to light, unknown if the same happened for Kaguya, or even if she knew of the eye's existence. Still the transfer of most powers were knowingly put into Hagaromo. Whereas the rest was given to Hamura, to be assumed, unknowingly or just through heredity. Through life, even if the story included more on Hamura, Hagaromo was deemed the stronger brother. My guess is that the "loser" child, is Hamura.
Inside of Naruto's mind, Hagaromo had explained the birth of both him and his brother. Where his mother, Kaguya, blessed him with all her powers and the rinnegan and passed down the Byakugan to Hamura. The strength of the Jyubbi was sealed in him giving him even more powers. Decades later Hamura is somehow on the moon and before death awakens a powerful eye that can rival the Rinnegan and the Rikudo's Sennin powers.
Two things that come to light, unknown if the same happened for Kaguya, or even if she knew of the eye's existence. Still the transfer of most powers were knowingly put into Hagaromo. Whereas the rest was given to Hamura, to be assumed, unknowingly or just through heredity. Through life, even if the story included more on Hamura, Hagaromo was deemed the stronger brother. My guess is that the "loser" child, is Hamura.