Hanzo

Hanzō also known as Sanshōuo no Hanzō ; Literally meaning ("Hanzo of the Salamander") is a legendary ninja from the time of the Second Great Ninja War. Little is known of his abilities aside from his riding on the head of a giant salamander (presumably a summon), but he was so powerful that he with his summon fought off all three Sannin. After their battle, he was so impressed with their strength that he decided to leave them if they agreed to accept the title of Sannin ("The Three Legendary Ninja"). He was later single-handedly defeated by Pein, despite the backing of Amegakure. Every person that he was ever connected to was systematically killed, and at this point there is nobody left.

Madara's Abilities

Most of Madara's abilities are still unknown. He is known to have an advanced Mangekyo Sharingan, and to make use of space-time ninjutsu speculated by Kakashi to be even greater than the Fourth Hokage's space-time ninjutsu. Since the Uchiha clan is known for its fire techniques, it is also speculated that he knows advanced fire techniques as well. He was armed with a giant fan during the time of Konoha's founding, which may explain the origin of a paper fan being the symbol of the Uchiha clan. He and Deidara were able to defeat the Three Tails, but Madara (as Tobi) was never shown doing anything but running away from it. After the battle, which goes largely unwitnessed, he claims to have knocked it out with a single attack. Deidara disagrees with the assessment, claiming that it was his "artistic contribution" (exploding clay) that allowed them to win. While as Tobi, Madara is also shown planting Deidara's clay minefields underground during a later battle. Itachi refers to Madara as being an "invincible immortal", which is further evidenced by continued existence despite his advanced age and his surviving the battle at the Valley of the End despite witnesses belief that he died.
Madara shows the ability to recover from what are presumably debilitating or fatal blows. After being slashed across the midsection by Sasuke's sword, he collapses, only to stand up again a few seconds later and complain about the speed of the attack, and later when Naruto hits him in the back with a Rasengan. The attacks literally phase through him, avoiding damage. He is also seen being hit by Sasuke's Amaterasu but emerging unharmed.
Madara also shows the ability to travel long distances within relatively short timespans, escaping the final explosion created by Deidara and reappearing in Amegakure, then travelling to the Valley of the End all within a very short time span. It is speculated by Kakashi and Sakura that he uses space/time ninjutsu to instantly send himself or even parts of his body to different locations or some sort of void and instantly bring them back. This was noted in his fight with Naruto, Sakura, Sai, Kakashi, Yamato, Kiba, Hinata, and Shino when Naruto attacked with a full powered Rasengan that phased right through him, and also when he escaped Shino's bugs even though they were completely surrounding his body. Second, when Madara criticized Zetsu's slow speed, Zetsu responds with a remark implying that his jutsu enables him to move at very high speeds.
After he escaped Deidara's final explosion, it is revealed that he possesses the Sharingan, shown visible through the opening of his mask. The demon fox mentioned that Madara's chakra was sinister, more sinister than its own. Madara was the only person capable of taming the demon fox which was said to only come where human malice collects and festers, yet he was able to use the Sharingan to tame the tailed beast.
During Itachi's fight with Sasuke, it is revealed that Madara Uchiha and his younger brother were the first members of the Uchiha to activate the Mangekyo Sharingan, and used its power to take over the clan. After implanting his brother's eyes into his own body, Madara then awakened a new "eternal" Mangekyo Sharingan, a combination of his own and his brother's Mangekyo Sharingan which gave him untold amounts of power without the risk of losing his eyesight. It was with this power Madara was able to forcibly subdue the demon fox. He is said to be the strongest Uchiha.

Tobi (Madara Uchiha)

To keep in Akatsuki's shadow, Madara eventually took on the guise of Tobi and was placed within Akatsuki as Zetsu's subordinate. As Tobi, Madara wears an orange mask, with swirls focused around the right eye, that covers his entire face outside of his right eye. Before wearing the swirl mask, Madara wore a similar mask, with markings across it, covering his entire face but the right eye.
Furthermore, Tobi has several bolts or pins present on the arms of his uniform, obscured by his Akatsuki cloak. While acting as Tobi, unlike others within Akatsuki, Tobi is carefree and goofy, but Madara uses a very formal and correct manner of speech.
While Tobi greatly respects his other members, referring to Deidara as Deidara-senpai in the Japanese version, most of the other members tend to get easily annoyed by Tobi. Deidara, who believes all within Akatsuki should be serious and calm, is not pleased with Tobi's childish personality, and frequently attacks Tobi in a comedic fashion when annoyed. Kisame, on the other hand, somewhat appreciates Tobi's ability to brighten up a gloomy organization such as theirs.
As Tobi, Madara has not been seen wearing a forehead protector, probably to seal his identity, though he already has a mask covering his forehead, so this could also be why it is not visible.

Madara's Personality

Madara sometimes exhibits a very calm and serious personality and at other times he exhibits a playful disposition, especially when in the guise of Tobi. He speaks with less formal diction, such as not using honorifics, and shows typically "villainous" arrogance. Despite this apparent arrogance, he is not above complimenting the abilities of Sasuke Uchiha and Naruto Uzumaki, if only for the interest of Sasuke's Sharingan and Naruto's tailed beast.

Despite his villainous personality, during the first wars he wanted to protect the Uchiha Clan and knew that the wars would eventually extinguish it, which is why, when the entire clan wanted it, he agreed on the peace treaty with the Senju Clan.

Madara Uchiha's Background

Eighty years ago, when shinobi were battling as individual clans, not as villages - among a countless number of them, two clans emerged as the strongest: the Uchiha clan and the Senju clan of the forest. Madara was born with a particularly strong amount of chakra, which he states due to his "stubborn refusal to die". His chakra was strong even for the Uchiha clan, who were known for having strong chakra. He was also the first to activate the Mangekyo Sharingan. He had a younger brother, who was equal to him in every way and who also awakened the Mangekyo Sharingan. Together they ruled over the Uchiha clan, with Madara taking the role as leader. But eventually Madara went blind, unaware of any side effects of the Mangekyo Sharingan at the time. He became increasingly desperate to regain his eyesight. He killed his brother and stole his eyes (although he claims that his brother willingly gave his eyes up to Madara for the sake of the Uchiha clan), so that he would have the strength to continue leading Uchiha. At some point in Madara's early life, by the decision of the entire Uchiha Clan except for him, he formed an alliance with the Senju Clan of the Forest, Hashirama Senju's clan, and together with its leader, the future First Hokage, Madara founded Konohagakure.
However, after Hashirama was chosen to be the First Hokage of Konoha, Madara feared that the Uchiha clan would lose supremacy and he sought the help of the Uchiha in his challenge for leadership. The Uchiha clan, however, refused, believing he was greedy, and called him a monster who stole his own brother's eyes just for his own desires. None of the Uchiha would help Madara, and he decided to leave the village. Feeling hurt, he came back and wanted revenge against Konohagakure which led to a legendary battle at the Valley of the End against Hashirama. During the battle, Madara used his Mangekyo Sharingan to take control of the Nine-Tailed Demon Fox and used it in a desperate attempt to kill the First Hokage. Madara, however, was ultimately defeated and was presumed by most to have died after the battle. Madara fled, and was never seen or heard of again out in the public for decades. To commemorate the battle, two statues, one of Madara and the other of the First Hokage, were carved into the earth around the waterfall. It is for this reason that Naruto Uzumaki and Sasuke Uchiha's fight at that location was noted to be ironic.
Madara created the criminal organization known as the Akatsuki to look over problems. He hid behind the shadows and placed Pein as the figure-head leader, with Madara giving Pein orders from the background. Outside of Pein, the only members who are shown knowing Madara's position as the true leader are Konan, Kisame, Zetsu and Itachi.
Itachi Uchiha believes it was Madara himself that controlled the Demon Fox to attack Konoha, though Madara denies this, saying that the fox was a natural disaster. Nevertheless, when he came to destroy the entire village of Konohagakure in revenge, he met up with Itachi, who had already been assigned his mission to kill his clan. Itachi successfully talked Madara into only killing the Uchiha Clan as long as he left the rest of the village alone. Madara also taught Itachi about the Mangekyo Sharingan, helping him by teaching him how to unlock its true power. After Itachi killed off the Uchiha clan because of orders from the Leaf Village, Madara let Itachi into Akatsuki for unknown reasons. Itachi refers to Madara today as "a pathetic shell of his former self, no longer worthy of being called the greatest Uchiha."
It has also been recently revealed that at some point after being presumably killed, Madara took the role of Mizukage.

Eight-Tailed Beast (Hachibi)

The Eight-Tailed Beast is currently one of the two remaining Tailed Beasts that were not extracted by Akatsuki, the other one being the Nine-Tailed Demon Fox. The Jinchūriki is a black, musclebound Cloud shinobi, who appears to dislike light. On his right shoulder, he has a tattoo that says "iron"; and on his left cheek, he has a tattoo of a bull's horn. He also carries seven swords. It also seems that he hates being called the host for the Eight-Tailed Beast, and prefers to be referred as "me and that thing". Killer Bee appears to be a physically strong man as he was able to wield Suigetsu's sword with great ease and was also able to take down Jugo during his curse seal stage.

Most of his abilities are still yet unknown, but it has been shown that he uses eight swords in a very peculiar manor. He places two swords in his hand, two on his elbows, two in his knees, one on his neck and the last in his mouth. This special maneuver allows him to attack his opponent with great speed and also in a circular faction, like a ball. Also, he is able to put chakra into his blades allowing them to up their power and also re transfer any other chakra being propelled by the opponent.

Hunt for Uchiha

Team Yamato would later be called into Tsunade's office where Jiraiya informed that Sasuke has killed Orochimaru. With joy, Naruto expects Sasuke to return to Konoha on his own, but Tsunade and Jiraiya tells him thats not the case. Naruto then asks Tsunade to form a team to hunt down Itachi Uchiha for a single purpose; Sasuke is after Itachi, if Konoha captures Itachi, Sasuke would have no choice but return home. Tsunade assigns Team Yamato, Kakashi, and the members of Team 8; Hinata, Shino, and Kiba to hunt down Itachi.

While searching, Naruto, Yamato, and Hinata were found by Kabuto. Kabuto tells them how without Orochimaru, he was left without a leader and has since made a resolve to make himself stronger. But to achieve this, Kabuto implanted Orochimaru's remains into his own body. Kabuto left the group vowing he would return to kill Naruto once he takes care of Orchimaru's killer. After this, the 8-man squad heard and followed a large explosion and went to investigate. Kiba informed them that Sasuke was there at that explosion and he could follow his scent. Unfortunantly, Karin sensed them coming and attempted to lead them off the trail by using Sasuke's old clothes and scatter them in different directions. Naruto used his Shadow Clone Technique to follow the scents, only to find Itachi. Naruto attacked Itachi, who only wanted to talk. Itachi asked Naruto why he cared so much about Sasuke to which Naruto explained that Sasuke was like a brother to him and he would be a much better brother to him than he (Itachi) could ever be. To this response, Itachi gave a rare smile (possibly because of what he had already sacrificed to protect Sasuke). Naruto again tried to attack him but was quickly caught in his genjutsu. Once again regrouping with the squad, one of Naruto's shadow clones was destroyed when Sasuke plowed through it, once again leading them to Sasuke's trail. While still following Sasuke the squad runs into Tobi, who taunts them playfully until Naruto attempts to attack him with a Rasengan. Instead, Naruto phases straight through Tobi. He is then apart of the battle group as they tried several different formations to take down Tobi, but all failed, leaving Shino to use his clans secret techniques to handle him. Tobi retreats when he hears of Itachi's death. Naruto's team rushes to the battlefield, to find Sasuke's scent mixed with the scent of the Akatsuki, and none of them present.

It was later revealed by Itachi that he had transfered some of his power to Naruto before he died. It is suspected he did this because he anticipated Sasuke's attack on Konoha. To what extent these powers have been granted is unknown.