Orochimaru was the main villain in Part I of the manga and anime series Naruto; though his role has diminished in Part II. Orochimaru's influence still effected the events leading to the Fourth Great Ninja War. He was voiced by Steven Blum in the English version and Kujira in the Japanese version.
Orochimaru was originally an orphan who became a pupil of Hiruzen Sarutobi, the Third Hokage, alongside Jiraiya and Tsunade. Compared to the more laid back Jiraiya, Orochimaru stood out as a prodigy found once in a generation. However, Orochimaru has a twisted and sadistic personality that may have been due to the death of his parents. At some point after losing them, Orochimaru found a white snake near his parents' grave and Hiruzen explained how it represented fortune and rebirth inspiring Orochimaru to obtain knowledge of all forms of ninjutsu.
During the Second Great Ninja War, Orochimaru joined Jiraiya and Tsunade in fighting Hanzo, who gave them the title of Konoha's Legendary Sannin for surviving their battle with him while the rest of their group were easily slaughtered in the process. On the way back to Konoha with his team, Orochimaru met Nagato and his friends who were orphans in the Land of Rain. While Orochimaru suggested killing the orphans in an act of mercy, Jiraiya stayed to train the children.
Some time after Team Hiruzen was disbanded, Orochimaru became an ANBU member and joined Root to work directly under Danzo Shimura while becoming a mentor to Anko Mitarashi. It was during that time that Orochimaru met Kabuto Yakushi while accompanying Danzō in forcing the boy's guardian Nonō into a mission. While Orochimaru's ambitions did include becoming the Fourth Hokage, he intended to use the title for his own agenda. Though Hiruzen knew the potential evil his former pupil had in him, he hoped to stir Orochimaru from the path before slowly realising that Orochimaru is beyond anyone's help. Sent on a mission by Danzo to ensure both Kabuto and Nonō, the former joining Root as a spy, kill each other as they have become major risks. Orochimaru instead spirited Kabuto to one of his many hideouts, what would become part of his personal hidden village Otogakure. Though Orochimaru reveals Root's intention for him to be dead, he explains to a horrified Kabuto that he sees a bit of himself in the boy and sees killing him to be a waste of great talent. Therefore, Orochimaru offers Kabuto a position as his right hand and spy with the promise of an identity for Kabuto to call his own. While working for Root, Orochimaru began an experiment to infuse Hashirama's DNA into a person, an early experiment in his attempt to gain the Sage's powers. However, he thought the experiment was a failure when all 60 babies he implanted with Hashirama's genetic code seemingly died (though there was an only survivor who became the ANBU known as Yamato).
With Kabuto's assistance, he performed various experiments on his prisoners, some being fellow Konoha shinobi he kidnapped. He uses them as human guinea pigs to develop techniques that would grant him immortality, the end result being the Transference Ritual where Orochimaru transfers his being into a host body every few years, allowing him to cheat death. Some time after, Orochimaru was at the outskirts of Kirigakure as he found Kimimaro, the sole survivor of the Kaguya Clan. Soon after, thanks in part to Kimimaro, Orochimaru's research on the source of Jugo's powers led to him into finding Ryūchi Cave and mastering Sage Jutsu. Unable to use it because of the fragility of his host body, Orochimaru instead developed an alternate method through the Curse Marks, testing it on Anko and his other students before using the finalised versions on Kimimaro and the Sound Four.
When Hiruzen finally retired and named Minato Namikaze his successor, Orochimaru saw no more reason to remain in Konoha and began to be less discreet with his actions. This led to his experimentation on the cultivation of Hashirama Senju's DNA with sixty children he kidnapped to recreate the First Hokage's Wood Style. However, as his test subjects begin to die off, Orochimaru was found red-handed by Hiruzen who knew it was his duty to kill him yet lacked the will to do so. Leaving Konoha and his emotionally broken mentor and despite Jiraiya's pleas for him to reconsider falling on deaf ears, Orochimaru left; unaware that Yamato survived his experiment.
Orochimaru soon joined the elite criminal organization Akatsuki, his role unclear but was partnered with Sasori whom he did much good for the Akatsuki with. However, when Itachi Uchiha joined the Akatsuki after conducting the Uchiha clan massacre, Orochimaru saw his opportunity to steal his body to gain possession of the Sharingan. Itachi used his Sharingan to reverse it while cutting Orchimaru's left hand off to prevent him from breaking the genjutsu, causing him to leave the Akatsuki to acquire a new body. Since then, with Kabuto posing as a sleeper agent that a infuriated Sasori sent to keep tabs on him, Orochimaru become an independent rogue ninja using the Hidden Sound Village to continue his experiments to achieve true immortality.