Orochimaru

Orochimaru is one of the Konohagakure's three legendary ninja or Sannin. He was the student that everyone believed would become the Fourth Hokage, but his hunger for power led him to commit dark experiments and practice forbidden jutsu. After the Third uncovered the truth, Orochimaru left Konoha and formed the Hidden Sound Village in the Land of Rice. He was responsible for countless immoral experiments and collected many ninja with unique abilities in his numerous hidden bases. He wished more than anything to find the ultimate body and improve himself to the state of a god. He attempted to possess Itachi Uchiha, Kimimaro Kaguya, and Sasuke Uchiha's body, but all of the attempts failed for various reasons, with Uchiha Sasuke actually reversing the jutsu and possessing Orochimaru's soul.

Background
Orochimaru was originally a student of the Third Hokage as a part of a three-man team consisting of himself, Jiraiya, and Tsunade. Team Sarutobi mirrored Team Kakashi in nearly every way. Orochimaru, like Sasuke, was kind as a child and a lot of his adult life, but became aloof, arrogant, and sadistic later on. Sarutobi in particular had very high hopes for him, often berating the clumsy Jiraiya and telling him he should be more like Orochimaru. After becoming Hokage, Sarutobi hoped that one day Orochimaru would succeed him.

While Orochimaru's ambitions did include becoming Hokage, his eyes were set upon goals quite alien to the ideals traditionally associated with the title and emphatically embraced by his teacher. Sarutobi knew that "a shinobi's true strength will manifest when protecting something important," and the Hokage's role is to love and protect the people of the village as if they were a family. For Orochimaru, however, Hokage was nothing more than a potential conquest on the way to what truly interested him - power.

Sarutobi hoped to make his student see the error of his ways, but the more time that passed, the more it became clear that Orochimaru was a lost cause. This culminated in Orochimaru kidnapping his fellow Konoha shinobi as human guinea pigs. He experimented on them to develop techniques that would grant him immortality, as he had already decided that he would settle for no less than to learn all jutsu in the world, a task that would take much more than one human lifetime. When the many disappearances were finally traced back to Orochimaru, Sarutobi knew that it was his duty to kill him, but at the time he simply couldn't bring himself to kill his prized student for whom he had had such high hopes. At the same time, he realized that Orochimaru was a twisted and power-hungry man that was not fit to fill the role of Hokage, and when he finally retired years later he chose a student of Jiraiya's, Minato Namikaze, over Orochimaru as his successor, making Minato the Fourth Hokage.

Realizing that he had hit a dead end in his quest to become the ultimate being and had nothing to gain from staying in Konoha, Orochimaru defected from the village and joined the elite criminal organization Akatsuki. His old teammate, Jiraiya, tried to convince him to reconsider, but to no avail - he betrayed the village and the title of the 'Three Legendary Sannin' was no more, though he is still known as one of the Legendary Three. The role Orochimaru played in Akatsuki is unclear, although it is known that he was partnered with Sasori prior to his defection, and they apparently had great respect for each other when they were partners. Sasori also claims that Orochimaru and him did a lot when they were partners in the organization. He then tried to steal Itachi Uchiha's body and almost succeeded, but underestimated Itachi's strength and Itachi turned the tables, paralyzing him and forcing him to flee the organization. Thus, he chose to go after the much weaker Sasuke Uchiha instead. He eventually founded his own village, Otogakure.

Plans for Revenge
For a while, Orochimaru left Konoha alone, plotting to destroy them when he was ready. The opportunity presented itself with the start of the Chunin exams. With this, Orochimaru saw both a chance to destroy his former home and acquire Sasuke Uchiha's body as his own. Having Sasuke's body would give him the Sharingan, which would aid him greatly in his ultimate goal.

Before the exams began, Orochimaru enlisted the help of Sunagakure, since his own village lacked the necessary strength to defeat Konoha. Already being weakened by their feudal lord, the village gladly accepted. Orochimaru later killed the Fourth Kazekage and assumed his place to get close to the Third Hokage.

During the second part of the Chunin exams, he entered the Forest of Death disguised as a Kusagakure ninja. During a confrontation with Naruto, Sasuke, and Sakura, he sealed Naruto's demon fox chakra and branded Sasuke with his Cursed Seal of Heaven. He was discovered by Anko, but the exams continued due to his threat of retaliation. His Genin team was sent to kill Sasuke, unaware that they were just measuring posts for Sasuke's power. They were fought off by a combined effort from Sakura Haruno, Rock Lee, and Team 10, who happened to discover them while Sakura was holding them at bay. Sasuke's awakening of his cursed seal caused them to retreat.

Endgame and Failure
During the final part of the Chunin exams, Orochimaru started his attack, hoping to unleash giant snakes outside Konoha while Shukaku was released from Gaara within the stadium. Things did not go as planned, however, and only the first of these occurred. During the attack, Orochimaru attempted to assassinate the Third Hokage. He even resorted to summoning the departed First and Second Hokages to attack his former master. After a long and spectacular battle, the Third attempted to seal Orochimaru's soul in the same manner as the Fourth Hokage had sealed the demon fox. Orochimaru, however, managed to impale his former mentor with his Kusanagi sword, weakening the Third to the point that he could only seal Orochimaru's arms, not his soul. This prevented him from using many of his techniques and left him in agonizing pain. Orochimaru's forces were also being repelled by the sudden appearance of all of Konoha's most powerful ninja, forcing a retreat.

Reunion
Initially, Orochimaru planned to have his condition healed by appealing to his old teammate, Tsunade, who had since become a legendary medical ninja. He offered to revive her brother and lover, both of whom died in battle, hoping it would persuade her to cooperate. Though it looked like he succeeded at first, it turned out that Tsunade actually intended to kill him rather than heal him. It was Kabuto Yakushi who interfered before she could do so. Strangely, Orochimaru almost seemed hurt by the betrayal, and remarked that he really would have brought her loved ones back and promised not to interfere with Konohagakure, a rarity considering his usual self-centeredness. After a large scale battle between him, Jiraiya, and Tsunade, in which all three of their largest summons were used, Orochimaru retreated. Since Tsunade wouldn't heal him, his only option left was taking a new host.

Sasuke's Defection
Though Orochimaru was right about Sasuke after all, who did eventually seek him out for power, Sasuke did not arrive fast enough to become Orochimaru's new container. With the pain in his arms and the constant decay and bleeding reaching the point when soon it wouldn't matter whether Sasuke arrived or not, Kabuto proposed that Orochimaru take a new host. Kabuto held a tournament of fights to the death between his prisoners and Orochimaru took over the body of the last man standing, Gen'yumaru. This, while getting rid of his condition, drastically delayed his plans for Sasuke, since he can only take over a new body once about every three years. When he took him over, he also noted that parts of Gen'yumaru's will and consciousness would remain in the new body's subconscious

Fight with the Four Tailed Naruto
After Sasuke's defection, he spent the nest two and half years training the boy to be his next body. When Team Yamato attempted to infiltrate his base for Sasuke, he reappears during a meeting between Yamato, disguised as Sasori, and Kabuto. Orochimaru explains that he had long ago undone Sasori's "Binding Jutsu" on Kabuto, and had intended assassinating his former Akatsuki Partner but never did. He then calls out Naruto, Sakura, and Sai to do battle. He explains that Yamato was the only one out of sixty test subjects that survived one of his genetic experiments to duplicate the First Hokage's Mokuton techniques and his previously unknown ability to "control tailed beasts", though he himself did not recognize this until Yamato revealed the abilities himself.

After antagonizing Naruto to the point where he transforms into a four-tailed state and attacks him, Orochimaru demonstrates a number of new abilities. As well as modified forms of snake summonings, he can shed his skin like a snake and, by doing so, repair any damage to his body, extend small snakes on his hands that can shoot powerful fire blasts, and absorb the strength of attacks thrown at him strengthening his body with the Soft Physique Modification Jutsu. He also demonstrates his immense reserves of chakra when he summons three Rashomon gates to block the Four-Tailed Strong Ball that the four tailed Naruto's spat at him. Though they failed to completely block the attack, it was still an impressive feat. Additionally, Orochimaru can create a Battle Clone out of snakes that can morph various parts of its body into snake parts. If injured, it can simply regenerate, and can be controlled from long distances by Orochimaru.

The battle with Naruto comes to an end after Orochimaru attempts to stab Naruto with his Kusanagi Sword. Even the sword is unable to pierce the intense chakra shield protecting Naruto. He comments that his body had reached its limit, as his current body is too weak to continue fighting. It is later shown at his lair, however, that the time he must rest for is quite short.

Afterwards, back at Orochimaru's lair, it is made apparent that Orochimaru plans to team up with the militaristic Konoha leader Danzo and destroy Konoha as it is today (the wording would seem to indicate a revolution or takeover, rather than outright annihilation). After a training exercise with Sasuke he interrupts Sai and Naruto, after they form a bond, to question Sai's loyalty. Though it seems like Orochimaru will resume his heated fight with Naruto at this point, he instead retreats, saying that he'll let Naruto go in the hopes that Naruto and company will take down more Akatsuki members for him. When Sasuke attempts to kill his former team with a new technique, Orochimaru and Kabuto appear and convinced him to spare their lives, at least until they kill more members of the Akatsuki. With Sasuke's "approval", they escape.

Defeat
After continuing their training, Orochimaru remarks that Sasuke is much stronger than he was at his age, and slowly began to lose health. Sasuke however sees this as his time to defeat his master, attacking Orochimaru when he was ill. Orochimaru revealed his true form, a giant white snake made up of smaller white snakes. Sasuke activates the second level of his Cursed Seal, and makes quick fights Orochimaru on even, demonstrating his maximum power. However, Orochimaru still manages to invade his mind and attempt at takeover, but the Sharingan allows Sasuke, with his great skill, to destroy the inner dimension of Ororchimaru. Sasuke greets a stunned Kabuto and tells him that while he didn't "officially" kill Orochimaru, he had taken over.

Later, when Kabuto meets Naruto, Hinata Hyuga, and Yamato, he tells them how he infused himself with Orochimaru's remains, which is now slowly taking over his body. What this means for Kabuto, and Orochimaru himself is currently unknown. Kabuto does say that the remains are hard to control.

Abilities
Being one of the Legendary Three Ninjas as well as a former member of Akatsuki, Orochimaru is a very talented ninja. The scope of his power is quite great, as seen through the Third Hokage's fears prior to the invasion of Konoha that nobody in the village would be able to defeat him in battle at that time. Likewise, Orochimaru is able to fight on an equal footing with a four-tailed demon fox form Naruto Uzumaki in Part II, and despite the danger Naruto imposes he finds the battle highly entertaining. While he has only displayed a limited amount of techniques, it stands to reason that in his efforts to learn all existing jutsu his array of abilities has become vast. One of the few jutsu he is seen using is the, which creates a copy of himself out of mud that can attack on his behalf. He is also able to utilize, through which he can level a wide area with a powerful gust of wind. In terms of defensive jutsu Orochimaru has created both and, in which he summons a varying number of large demonic gates that are capable of enduring the most intense forms of damage. If need be he can also place a on an opponent, sealing off their access to chakra and thus making them useless in battle.

In his quest to gain immortality Orochimaru has made a number of modifications to his body, resulting in his natural form taking on the appearance of a giant white snake composed of many smaller snakes. This form has the advantages of allowing him to stretch any part of his body to great lengths, regenerate any wound inflicted upon him, and otherwise use the snakes that he is composed of for attack. The primary use of the form is with his, which allows him to transfer his soul to another's body and extend his life indefinitely. To use this jutsu Orochimaru leaves his former body, revealing his true form. Once doing so he swallows the new body and transports its current inhabitant to a dimension within himself where he absorbs them, thus allowing him to use their body. Orochimaru can only perform this technique once every three years, which is also around the time that his new body begins to reject him and forces him to find a new host. Although he might leave their bodies behind, the souls of those whose bodies he has taken always remain within Orochimaru's subconscious, causing some of their traits to affect the choices he makes. While within another's body Orochimaru uses to assume his original appearance. This ability also allows him to take the identities of others by forcefully peeling off their face for his own use, killing them in the process.

As a byproduct of his research to gain immortality, Orochimaru developed the, which allows him to revive the dead. To perform the technique Orochimaru must sacrifice a living human so that the soul of the deceased person can be tied to the living world. The sacrificed body is then surrounded with dirt and dust that compacts into the shape of the summoned soul's original body. Although the revived retain their original memories and personalities, thus leaving them out of the control of Orochimaru, Orochimaru can suppress their free-wills with his own special seal to force them to do his bidding. The bodies of the resurrected are also able to regenerate any wound, meaning the only way to defeat them is to remove the soul within them.

Orochimaru has an apparent interest in snakes that, in addition to impacting the appearance and composition of his true form, has caused him to learn a number of snake-related abilities. One such ability is being able to summon giant snakes to fight alongside him in battle, made possible by the summoning contract tattooed to his arms. With and the larger-scale, Orochimaru can call forth snakes from his sleeves and mouth to attack opponents in large numbers with poisonous bites. Another usage of snakes comes in the form of his, the Kusanagi of Japanese legend. The sword, kept within a mouth of a snake within his own mouth, is able to extend to great lengths and can be controlled remotely by Orochimaru. Although he is capable of using the sword normally with great proficiency, it is not uncommon for him to wield it without ever removing it from his mouth. In addition, Orochimaru has shown the ability to regurgitate copies of himself from his mouth. His, while not directly connected to snakes, allows him to show opponents visions of their own gruesome deaths, making them immobile with fright, causing them great mental stress, and allowing him to kill them at his own pace.

Trivia

 * Orochimaru borrows heavily from Japanese literature — his name, as well as those of Jiraiya and Tsunade come from the Jiraiya Goketsu Monogatari (児雷也豪傑物語, "The Tale of the Gallant Jiraiya"), and the Orochimaru in that story was originally Jiraiya's student until he was corrupted by snake magic.