Tobi (Obito Uchiha)

"The moment people come to know love, they run the risk of carrying hate." - Madara Uchiha

Madara Uchiha is an extremely powerful ninja shrouded in mysteries, who serves as the primary antagonist in the Naruto franchise. Madara was once the leader of the famed Uchiha clan and the co-funder of Konohagakure, the Hidden Village of the Leaf, but his bellicist view and his hatred of Harashima Senju, the First Hokage, estranged him from his own clan, prompting him to desert the village, which he swore to destroy. Madara resolved to gather the nine Tailed Demons and use their power to cover the entire world with a Tsukuyomi genjustsu to control it as a God. Despite appearing very late in the story and first being seen under a fake persona, Madara is the founder and actual leader of Akatsuki and is more or less directly responsible for the attack of the Kyubi and the Massacre of the Uchiha Clan, as well as many other horrible events all over the ninja world, which he manipulated from the shadows.

The Sage of the Six Paths
Despite not being part of Madara's actual history, the legend of the Sage of the Six Paths is a major driving force for Madara's actions, as he more or less plans to become his successor and continue his work, albeit following Madara's disturbed views.

The Sage of the Six Paths was a legendary ermit of unfathomable power who lived millenia before the start of the story, and who is believed by almost everyone to be pure myth and superstition. He was said to have the Rinnegan (the most powerful hereditary power in the world, whose only other owner was Nagato) and is also famous for having created the Ninjustsu, which he taught to mankind.

According to Madara, the Sage of the Six Paths fought and defeated the fearsome Ten Tailed Demon known as the Jubi, which he sealed within himself. Near the end of his life, the Sage feared that the Demon would be released again, so he divided the Demon's immense chakra (ki) into nine separated parts that would become the Tailed Demons known as the Bijus. He then cast the Demon's body into space where it formed the moon. After the Sage's death, each of his distinct powers (the Six Paths) were tranmitted to mankind and eventualy came to number among Madara's targets, as the villain plans to gather them all.

Madara's ultimate goal, the "Eye of the Moon Plan" is to gather all the Tailed Demons and to fuse them back together, in order to become the Ten Tailed Demon's new host and gain access to the moon, where he would be able to use the demons's immense energy to live forever and cast an everlasting Tsukuyomi spell on the entire earth, gathering all creation under his control and becoming a God in all sense of the terms. He callously claims that trough this he would be able to achieve global peace and utopia, though those whom he tells this onlry react with a disgusted mistrust.

Early Years
Madara Uchiha was born around a century before the start of the story. At the time the Ninja World was locked in a permanent state of war, each Country ruler wanting to extend his influence at the expense of others, and the Ninjas were organized as huge clans of mercenaries, hired by said lords as their major assets. Among the many powerful clans of these times, the strongest were the Uchiha and the Senju of the Forest. These two clans were so powerful that the only force able to resist one was the other, leading each lord to hire one whenever the other was hired against him. (According to Madara, both clans descend from the Sage of the Six Path's two sons, one born with the Sage chakra, who favored force, the other born with the Sage's strength who favored love and was selected as the Sage's successor, much to his brother's ressentment.)

Madara numbered among the most talented ninjas of his clan. He and his brother Izuna eventualy awakened the Mangekyo Sharingan and with his their newfound powers, they were appointed as the rulers of the Uchiha Clan. To his horror, Madara discovered that using the Mangekyo Sharingan was rendering him gradually blind and that transplanting his brother's Mangekyo Sharigan on his own was the only way to restore his eyesight, and so he did. (Madara alleges that Izuna willingly relinquished his eyes, but he is a master liar and according to the much more reliable Itachi Uchiha, he took Izuna's eyes by force.)

The Funding of Konohagakure
Now the undisputed leader of his clan, Madara had to supervise every battle between the Uchiha and the Senju, he himself having to fight against the Senjus' leader Harashima more times than he could remember. Over the years, Madara developped a strong respect and a even stronger hatred for Harashima, whom he regarded as his rival. But eighty years before the start of the story when the Senju approached the Uchiha and offered them peace so that they could found together Konohagakure, the Hidden Village of the Leaf Madara agreed.

So the Hidden Village of the Leaf was created, following their example, all the ninja clans of each country formed an alliance to create the different Hidden Villages, leading to a stability never seen before. Yet, Madara was bitter and ressentful towards Harashima Senju, who was appointed as the first Hokage (lord of Konohagakure) instead of him. He was unable to forget the two clans hateful history and feared that as the Senju were in a higher position of power, they would use it to deprive the Uchihas of any authority and and keep them under their control. However, even his own clan regarded his mistrust as a warmongering paranoia and he lost much of his credit among them. Even when Harashima's brother and successor appointed the Uchihas as the village's secret services and police, he regarded it as a facade and a confinment.

Madara's downfall
At some point, Madara deserted the village and began to plot its destruction. Harashima Senju pursued him and the two led their ultimate battle at the Valley of the End. Despite being in control of the Kyubi (the Nine Tailed Demon Fox) the most powerful of the nine Tailed Demons Madara lost and was grievously wounded, everyone assuming him to be dead. Since then, the people of Konoha erected two immense statue of Harashima Senju and Madara Uchiha in the cliffwall, permanently facing one another at both side of a waterfall, as a symbol of their neverending rivalry.

However, Madara survived and went into hiding, even managing to steal a sample of Harashima's cells to copy his unique ability to create and control trees and wood. Since he was according to his own word a "shadow of his former self" he began to hatch a plan which would not only allow him to enact his revenge against Konohagakure and the Senju and gain a power even higher that the one he one had, but also to mold the entire world following his twisted ideals.

The Uchiha Clan Massacre
Madara planned to unleash the Kyubi on Konoha and waited for its former Jinchuriki (host) Kushina Uzumaki to give birth, so that he could take profit of the weakened seal to release the demon. He made quick work of Kushina's bodyguards and took Naruto - Kushina's newborn son and soon-to-be eponimous primary protagonist - to enact his goal. Minato Namikaze - Naruto's father and Konoha's fabled fourth Hokage - managed to get back his son and later gave up his life in order to seal the beast within his own son, hoping that Naruto would one day be able to use the demon's power against Madara.)

Konoha wasn't destroyed but Madara's main goal was achieved. Given that the Uchiha wield the power to control the Kyubi, the villagers came to believe that they summoned him and shunned the clan. Irked, the Uchihas staged a secret coup d'état to take over the village, exactly as Madara expected, chosing their most talented prodigy Itachi Uchiha to infiltrate the village's highest spheres of influence. However, Itachi was a pacifist and feared that the coup would escalate into a Fourth Great Shinobi War, prompting him to become a double agent and to willingly sacrifice his honour and reputation and to slaughter his entire clan as the third Hokage's advisors had ordered him.

Itachi, who knew that Madara Uchiha was behind the Kyubi's attack came to see him and offered him to participate in the massacre and enact hsi revenge against his clan, in exchange of a promise that he would do nothing against Konoha. Itachi became Madara's disciple of some sort and likely upon his advices, he awoke his Mangekyo Sharingan. Then, they slaughtered the clan, but Itachi could not bring himself to kill his younger brother Sasuke Uchiha and spared him.