Reanimation Jutsu was Nagato's strongest technique.
'Naruto Uzumaki' still remembered Nagato from back then.
He had used this technique to summon King Yama from the underworld into the world of the living, making him stand up and open his great mouth to release the souls of countless dead. He returned those souls to their bodies, reviving the dead.
However, this technique required the caster's life as its price.
Nagato had died because of it.
Now that 'Naruto Uzumaki' heard Naruto wanted to use this technique to revive his parents—his parents from that world—he had initially been unwilling to give Naruto the Reanimation Jutsu.
But then he considered that Naruto's strength had surpassed his understanding.
Perhaps Naruto had a way to solve the drawback of the caster dying and could give him a surprise.
When 'Naruto Uzumaki' had first learned of this technique, hadn't he also wanted to use it to revive his own parents?
But Nagato had died because of it, so he had abandoned that thought.
Exchanging the caster's life for his parents' resurrection already violated Naruto's bottom line.
The Impure World Reincarnation was the same. It was a technique that desecrated the dead and required the bodies of innocent people as sacrifices. Although 'Naruto Uzumaki' did not know the Impure World Reincarnation, he had likewise never had anyone use it. It went against his original intention of protecting Konoha.
If his father, Minato Namikaze, knew that he had sacrificed innocent people in order to revive him, then his father would never forgive him.
Naruto did not know what 'Naruto Uzumaki' was thinking, but he shared the same principles. He had never disregarded life. Although he had killed those from Hiruzen Sarutobi's faction, it had only been for revenge.
Naruto would never slaughter innocent people without reason simply because