Yahiko
Yahiko (弥彦) was a shinobi from Amegakure and once a student of Jiraiya along with Nagato and Konan.
The three eventually encountered Jiraiya, who looked after them and taught them basic ninjutsu. At one point, Nagato saved Yahiko after an Iwagakure chūnin attacked them. Afterwards, Yahiko vowed to become strong enough to protect Konan, Nagato, and eventually all of Amegakure.
Some time after Jiraiya’s departure from Amegakure, the three gained a reputation as a talented shinobi team. Still desiring to create a world of peace, Yahiko and his friends went on to become fully fledged Ame ninja, and gathered many supporters who shared their hope to save their village and the world.
Among the three Ame Orphans, Yahiko seemed to act as the leader of the group. It was Yahiko who first approached the Sannin to ask for food, and was the first to ask Jiraiya to teach them ninjutsu. He also seemed to act as an older brother for Nagato and Konan, reminding Nagato to not cry and to act more manly (although Yahiko was the one who cried when Jiraiya left them). He also wished to become stronger so as to protect Nagato and Konan. He had faith in Nagato, when he got older.
Yahiko eventually united them together with the name of Akatsuki, an idea Madara Uchiha claims to have given him. Akatsuki spread their beliefs to stop war without violence, and news of their actions would reach Jiraiya from time to time. Their group became so well renowned that even the then leader of Amegakure, Hanzō, started to view Yahiko and his supporters as a threat to his power. Working with Danzō during the Third Shinobi World War, they captured Konan and forced Nagato to choose to let Hanzō kill Konan or for Nagato to kill Yahiko himself. Without hesitation, Yahiko drove himself into a kunai that Nagato was holding. With his final breath, he told Nagato to continue their mission of finding peace.
After his death, Nagato using his Rinnegan and chakra receivers, incorporated Yahiko’s body into his Six Paths of Pain technique. As the Deva Path, Yahiko’s body had acted as Pain’s main body, it being the one he most commonly used and spoke through. The Deva Path was held in higher regard during combat, some of the other bodies being sacrificed to ensure its survival. It has a wide variety of ninjutsu, the most prominent being able to manipulate gravity.