Nagato grew up as a sensitive child, prone to tears from the suffering of those around him. Under Yahiko's influence, he tried to suppress this trait, but Jiraiya later convinced him that the ability to feel others' pain is a strength that allows one to be kinder. In his youth, Nagato hated killing and was shocked by his first forced killing, but to protect his friends he overcame himself.
After Yahiko's death, Nagato changed drastically. He took the name Pain, declared himself a god, and took on the mission of bringing peace to the world through pain. He is convinced that people will never understand each other without shared pain, and is therefore ready to destroy entire villages to create brief periods of calm in the endless chain of hatred. Despite the cruelty of his methods, he retains remnants of his former nobility: he is merciful to those willing to cooperate, grieves for his fallen Akatsuki comrades, does not approve of insults toward his allies, and treats strong opponents with respect.
As the leader of the Akatsuki, Nagato radiates charisma and calm confidence. He is patient with Hidan's insolence, calling his behavior childish, and does not hesitate to enter battle with any opponent. In conversations about the nature of war he is reasonable and even philosophical, but his views on humanity are pessimistic: he believes reasons for war will always be found because conflict is embedded in human nature. Deep in his soul, however, he realizes that he himself remains merely an ordinary human seeking peace through the means available to him.