D

is a former refugee to the Land of Mountains from Kumogakure and later became an elder of Yamagakure. He is the leader of the mysterious ANBU faction "Summit".

Background
D was born in Kumogakure, however, during the break out of the, his family fled the Land of Lightning; seeking refuge in the neutral Land of Mountains — specifically, its capital of Edo. There, he met Chiyo, who became his close friend, always tending to him when he was hurt, or scolding him when he got in over his head. He also met Nagato Yorozuya, who would become his best friend and fiercest rival. The three formed a team and grew close, all three becoming chūnin, though Nagato became a jōnin soon after, much to D's jealousy. War broke out yet again, this time in the Land of Mountains, as Ryun Uchiha attempted to rally the nation's shinobi together to create their own hidden village; Yamagakure. Along with his teammates, D joined the conflict on the frontlines. During peacetime, D developed a strong rivalry with Nagato, and the two frequently fought to prove which was the more powerful shinobi. One such fight broke out in the middle of the village, and it was rumored that the Yamakage himself had to intervene to prevent them from damaging the village's infrastructure.

Their rivalry grew more intense once both men realize that they were both in love with the same woman; Chiyo, whom they had grown up in Edo with, and whom had come to accept them both as her closest friends. However, much to D's dismay, Chiyo slowly began to fall for Nagato, and before long, the two stopped their constant fighting so as not to drag her into their bitter conflicts. Nagato went on to marry Chiyo, though D happily attended their wedding. Only a few years after the ceremony, the Samurai–Shinobi Civil War broke out between the remaining samurai, aiming to keep their way of life, and the rising bud of the shinobi, who were beginning to take root all over the Land of Mountains, thanks to Yamagakure's influence. Nagato, Chiyo, and D were sent to the frontlines, only for them to become separated during the fighting. D arrived in time to back Nagato up, however, he failed to miss a stray explosive tag, attached to a kunai, and Nagato threw himself in the way to protect him. The resulting explosion fatally wounded Nagato, and, as he died, he asked D to protect Chiyo and his son for him, as well as to always remain loyal to the village. Secretly, however, D took a sample of Nagato's DNA, somehow incorporating it into himself, in the hopes of preserving his comrade's former prowess with the Scorch Release.