Madara Uchiha
Madara is a member of the Uchiha Clan, one of the strongest clans of the village of Konoha. During his childhood, he met a child named Hashirama and become his friend. The two compete with each other to become strong. Together they envisioned a village where ninjas will not kill each other. After learning that Hashirama is a member of the Senju Clan (enemy of the Uchiha Clan), their friendship ends. After failing several attempts to defeat his rival, Madara accepts Hashirama's treaty offering of peace between the Uchiha and the Senju. They founded the village of Konoha. But their methods about peace differs. After his defection from the village, Madara challenged Hashirama again and a massive battle occured at the Valley of the End. Madara, believed to be killed in the battle, when into hiding for several years. While hiding, he planned to create a world of peace where there is no fighting and killing between ninjas. He was already old when he activated the Rinnegan eyes. Because there's no time left, he transplanted his eyes to the young Nagato (to preserve the eyes for his later revival) and takes Obito Uchiha as his agent to accomplish his plan. He then entrusted Obito to use his name, Madara Uchiha.