You said something interesting that I wanna put a "what if" to. We know that red hair is an uzumaki trademark but everyone with red hair isn't an uzumaki AND ever uzumaki doesn't have red hair. Now from your theory we get there were no host before the uzumaki, so that made them the first host. If you could seal that power in your own people why share it. are it. It's better to assume that all the first hosts were Uzumakis and that's what led tthe demise of their people. The uzumaki's are the only ones capabl of econtaining the tailed beasts. Who are the older jins we know. Mito, Kushina, Gaara's mom (could have easily been auzumaki) everyone else was younger that we've seen. Help that could also explain why nagato was chosen for the rinnegan. Only an uzumaki could handle being a host and live. Not everyone chosen to be a host of any kind was able to contain the beasts and live. Madara had rinnegan and died soon after, obito has his one rinnegan in his zetsu half, makes you wonder why he didn't implant both eyes, only person we know to live with a rinnegan is Nagato
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