Orochimaru:
Orochi means "Eight-Forked Serpent" and Maru is a common suffix in male names.
Orochimaru was originally a student of the Third Hokage as a part of a three-man team consisting of himself, Jiraiya, and Tsunade. From a young age, Orochimaru's stood out as a prodigy. His talent, brains, and determination was considered by his sensei a sight seen once a generation. Team Sarutobi mirrored Team Kakashi in nearly every way with Orochimaru being the indifferent geninus of the group. Orochimaru was kind as a child and for a lot of his adult life, but later grew to become aloof, arrogant, and somewhat sadistic. His sadistic attitude was, presumably due to the death of his parents, which led him to study kinjutsu. Jiraiya theorized that Orochimaru went down this path in an attempt to forget about his painful memeories. Sarutobi in particular had very high hopes for Orochimaru, often berating the clumsy Jiraiya and telling him he should be more like his teammate. After becoming the 3rd Hokage, Sarutobi hoped that one day Orochimaru would succeed him.
While Orochimaru's ambitions did include becoming the 4th 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 as more time passed, it became evident 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. At the time however, Sarutobi was unable to bring himself to kill his prized student for whom he had had such high hopes for. When Sarutobi finally retired years later he chose a student of Jiraiya's, Minato Namikaze, over Orochimaru as his successor, thus making Minato the Fourth Hokage.
Realizing that he had hit a dead end in his quest to become the ultimate being and therefore had nothing to gain from staying in Konoha, Orochimaru defected from the village and joined the elite criminal organization of 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' (although he is still known as one of the Legendary Three). Although the role Orochimaru played in Akatsuki is unclear, it is known that he was partnered with Sasori prior to his defection (the two apparently had great respect for each other when they were partners; Sasori also claimed that Orochimaru and him did a lot when they were partners in the organization). It was around this time that Orochimaru tried to steal Itachi Uchiha's body. Orochimaru was able to use his Living Corpse Reincarnation Technique, but Itachi used his Sharingan to reverse it and damage Orochimaru's body, causing him to leave Akatsuki to acquire a new body. Thus, he set his sights on Sasuke Uchiha. He eventually founded his own village, Otogakure.
It was revealed that some time before his invasion upon Konohagakure, Orochimaru had tricked Arashi Fuma and some of the Fūma clan to serve him by saying that he would restore their clan to their former glory. After Kagero Fuma, Kamikiri Fuma and Jigumo Fuma's failure to kill Naruto, Jiraiya, and Sakura, Orochimaru killed Kamikiri and Jigumo and later absorbed them into Arashi. Kagero was healed and posed as Kabuto in her confrontation with Sakura. Orochimaru then appeared before Team 7 after Kagero's death. However, it turned out that the "Orochimaru" who was observing the events taking place in the palace was actually the now power-crazed Arashi in disguise. After a long battle, Arashi was defeated and they discovered that Orochimaru was no longer there.
During Orochimaru's past with Anko Mitarashi, he chose her and nine others to bare his then-newly-obtained Cursed Seal Mark to determine who, out of the ten, would be worthy of becoming his apprentice and, eventually, human vessel. Anko, at that time, respected and admired Orochimaru, typically referring to him as "Orochimaru-sama" (Lord Orochimaru in the English dub) and while he might not have cared for her and viewed her as just another vessel for him to take over, he trusted her enough to show her one of his human experiments (later revealed to be Isaribi) before he gave her the Cursed Seal. Though, he might've done the same thing and acted the same way with the other nine "candidates" so that he could build their trust and eventually transform it into devotion as with Kimimaro many years later. Soon after he showed her one of his experiments, he tested his Cursed Seal on Anko and the other nine, and gave her the Cursed Seal of Heaven. After he found her as sole survivor, he estimated the 10 % chance of surviving given a cursed seal. Most of Anko's memories of her time with Orochimaru were erased, due to the Cursed Seal, and Anko could only come up with the conclusion that he abandoned her and left her to die afterwards, while in reality, he gave her the option of coming with him, or staying behind. She chose to stay, and not go with Orochimaru.
At one point, in between his encounter with Anko and his succession from Konoha, Orochimaru became interested in creating an invincible army of mutated underwater ninja to give Konoha shinobi the ability to breathe, fight, and operate underwater. Realizing it would take too much time on his own, Orochimaru contracted with a rogue medical ninja/scientist named Amachi (with similar ambitions), began terrorizing the people of the Land of Sea and kidnapped several citizens, notably Isaribi, for their experiments. Eventually, after Sasuke joined him, Orochimaru lost interest with the experiments and ordered Amachi to shut down the project during their last encounter with each other. Amachi, however, secretly refused and continued the experiments without Orochimaru's notice. Feeling cheated out of both his money and time, Amachi planned to use the water-shinobi to exact vengeance on Orochimaru and sent Isaribi to spy and attack ships carrying gold, making her believe that through these deeds, Amachi would return her to her normal human form, when in reality, he planned to dissect once she is no longer of any use. Afterwards, Amachi enlisted the aid of Kabuto's former shinobi partners Yoroi Akado and Misumi Tsurugi who served as bodyguards. Later, during the Sea Country arc, Amachi was defeated by Naruto and subsequently arrested by Anko's team. Misumi was assumingly crushed to death after Ino Yamanaka tied his arms to some poles in an exploding lab, while Yoroi possibly drowned after his oxygen supply was cut off when Shino Aburame poured bugs down his throat. Isaribi was able to make her come to her senses due to Naruto's insistence and returned with Naruto to Konoha after Amachi's defeat hoping that Tsunade could cure her, which she presumably did.
With Sasuke's "approval", they escaped.
While their training continues, Orochimaru watched as Sasuke defeated a large army of ninja alone, remarking how Sasuke was much stronger than he was at his age. Meanwhile Orochimaru slowly began to lose his health. Sasuke saw this as an opportunity to leave Orochimaru (as Sasuke believed he has nothing more to learn from him), and attacked him while bedridden. Orochimaru proceeded to reveal his true body: a large white snake made of several smaller snakes. Sasuke responded by activating his Cursed Seal and destroyed the giant snake's body. Orochimaru then initiates his Living Corpse Reincarnation Technique. However, using his Sharingan, Sasuke was able to control the inner dimension of Orochimaru and suppressed him. Sasuke greets a stunned Kabuto and told him that while he didn't kill Orochimaru, he had taken over. Since his defeat, Orochimaru was suppressed by Sasuke's chakra. During Sasuke's fight with Itachi, though, he used up almost all of his chakra, and Orochimaru forced his way out of Sasuke. However, before he was able to defeat Itachi and then take Sasuke's body, Itachi used the Totsuka Sword of his Susanoo to seal Orochimaru away, removing Sasuke's Cursed Seal in the process. When Kabuto met Naruto, Hinata Hyuga, and Yamato, he told them how he infused himself with Orochimaru's remains, which are now slowly taking over his body, and hopes to take Orochimaru's power and finish his master's goals as a leader and not a follower.
Being one of the Legendary Sannin as well as a former member of Akatsuki, Orochimaru is an extraordinarily powerful ninja. He was originally selected to become the Fourth Hokage, but the Third feared the evil within him, and gave the position to Minato. His power is so great that around the time of of his invasion of Konoha, the Third feared that no one alive from Konoha could defeat or even fight on equal footing with him, even the Third himself. During the fight with his former teammates he was able to subdue Jiraiya as well as withstand a horrible beating from Tsunade while his body was in an extremely weakened condition (although Jiraiya was weakened by Tsunade's drug at the time). Orochimaru was also able to fight on equal footing with a Four Tailed Naruto Uzumaki in Part II while his body was in a weakened state, and despite the danger Naruto imposed, he found the battle highly entertaining.
Due to him rarely been shown fighting, he has only displayed a limited amount of techniques, although it stands to reason that in his efforts to learn all existing jutsu, his array of abilities has probably become larger than any other single character, even Kakashi Hatake and the Third Hokage, who were both praised for knowing over 1,000 techniques. His knowledge of jutsu ranges in all forms beyond conventional ninjutsu. During his first battle, he demonstrated unique genjutsu prowess on Sasuke and Sakura, and later revealed equally impressive sealing jutsu prowess by tampering with Naruto's access to the Nine-Tailed Demon Fox.
One of the few techniques he is seen using is the Earth Clone Technique, which creates a copy of himself out of mud that can attack on his behalf. He is also able to utilize Wind Release: Great Breakthrough, through which he can level a wide area with a powerful gust of wind. In terms of defensive techniques, Orochimaru uses both Summoning: Rashomon and Triple Rashomon, 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 Five Elements Seal on an opponent, sealing off their access to chakra and thus rendering 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. One of his former ninja, Misumi Tsurugi, knows a less sophisticated version of this technique (though unlike Orochimaru his version is limited). The primary use of the form is with his Living Corpse Reincarnation, 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 he has done this, 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, even if only slightly. While within another's body, Orochimaru uses Vanishing Facial Copy Technique 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 he did with the 4th Kazekage and Shiore's team.
Orochimaru can use Summoning: Impure World Resurrection, 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 Hidden Shadow Snake Hands, 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 Kusanagi Sword: Long Sword of the Heavens, the Kusanagi of Japanese legend. The sword, kept within a mouth of a snake within his own throat, 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 Death Foreseeing Technique, 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. This technique is stated to be pure killing intent instead of an actual ninjutsu in the anime and manga, which is further implicated by the fact that Sasuke Uchiha could perform this technique while he has only seen it with his Sharingan unactive.
