Okay,so where does it states that Obito is going blind too? 'Hashirama's Cells are preventing it.Unless you meant he got both Kamui eyes, but still no both Kakashi and Obito are going blind in their sharingan.
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I beleive op is taking about sharigansNo he wouldn't be unbeatable but the war would be won. You're probably thinking he would be unbeatable because of his kamui, but remember that's only because of his sharingan powers. With both rinnegan he wouldnt be able to use that power.
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rinnegan cant touch both kamui'sHe would be more powsrful than Akatsuki(MS) Obito, but less powerful than war arc(MS/Rinnegan), since Rinnega>Sharingan
If Obito's have both his eyes, I believe he will be unbeatable.. what's your opinion??