IV - Love
Nagato's anger didn't go unnoticed.
And maybe that's why he was here now, watching his son sleep. He didn't know his intentions. He knew nothing about him. The father side of him wanted to find out, but his consciousness told him not to: he had to kill him in the end. And at all this his heart ached.
Nagato was his long lasting gate. And if by 'loving' Pein he can spare his life, even with the cost of casting him away, he will. No need to face death of family again. The ones he had already hanged down heavy on his shoulders. Not his son.
And maybe if he wasn't the man he was the Uchiha would have caressed the blood-head of this