Obito.
If Obito had both Kamui's, he'd be too OP.
That's why Kishi had to split his powers with Kakashi.
Naruto because he can multiply his power.
Hashi > Hiruzen
so yeah Hashi
No he can split up his power
You make no sense.
It's an obvious attempt to provoke you. <3
Nagato, he was so OP that Kishimoto had to cripple him, and drain his chakra reserves.
Naruto will be more OP though.