Hello everyone. I'm new here and this is my first post so please go easy on me :o
I'll straight away cut to the chase : Everyone who had Mangekyou Sharingan had their eyesight deteriorated after using it extensively. However, Obito's eyesight is fine (He hasn't showed any sign of eyesight deterioration yet) (even though he has used Kamui for so long). Could this be due to him having Senju DNA?
Same lies for Kakashi....perhaps he too is somehow related to Senju hence his eyesight is fine as well.?
Once again, I'm just sharing my idea...So please go easy on me