Kabuto Yakushi

is a character in the anime and manga series Naruto.

Kabuto is the last part of the Japanese name for aconite, a plant which can either alleviate pain or kill, an apt description for his character. Additionally, a kabuto is also the name for a samurai's helmet or headplate. With his former teammates, Yoroi ("armor") and Tsurugi ("sword"), they form an armor-helmet-sword trio. Kabuto can also refer to a rhinoceros beetle. His family name, Yakushi, is the Japanese name of the Medicine Buddha, Bhaisajyaguru.

Background
Kabuto Yakushi is a character whose origins are largely unknown. As a young boy, Kabuto was found amongst the enemy dead after the Battle of Kikyo Pass by a chief medical officer of the Konoha Medical Unit Squad. The officer brought Kabuto with him back to Konoha, raised him as a son, and taught him medical jutsu when he got older. At some point in time, Kabuto was recruited by Sasori of Akatsuki, who sent Kabuto to spy on Orochimaru by using various jutsus to transform him into a sleeper agent. Orochimaru discovered this, and released Sasori's Brainwashing Investigation Technique over Kabuto's memories, leaving Kabuto with the option to follow him. With a little persuasion, Kabuto agreed to side with Orochimaru.

Kabuto has assumed the position of Orochimaru's personal medic, assistant, and general right-hand man. He also serves as a spy for Orochimaru, playing the role of Sasori's servant to gain knowledge of Akatsuki's plans. Through his affiliation with Konoha, Kabuto was also able to acquire the rank of Genin and enter the biannual Chunin Exams, using the first two parts of the exam to gather information on his fellow participants for Orochimaru's use. Additionally, with the medical expertise taught to him by his adoptive father, Kabuto is able to carry out human experiments for Orochimaru, while at the same time increasing his own knowledge of the human body.

Loyalty and Personality
Kabuto's loyalties and personality are difficult to discern, as he is a sadistic, yet polite, helpful, and humorous man. He enjoys playing mind games with his enemies, often unnerving them by pointing out their weaknesses and turning personal horrors against them. He seems to have a hard time tolerating rudeness though, as demonstrated when Sasuke Uchiha meets Sai of Konoha, Sasuke goes far enough to repel Sai's efforts to be his friend, he enters Sai's subconscious with his Sharingan and scares him with cold, heartless messages and killing intent, which Kabuto easily became upset with. Orochimaru also seems to have a hard time determining Kabuto's thoughts at times, as seen when he orders Kabuto to kidnap Sasuke, and wonders if perhaps Kabuto will kill him instead, even giving hints that now would be an opportune time to halt his plans. Even in this instance, Orochimaru has great confidence in Kabuto's loyalty, often laughing at the prospect that Kabuto would betray him. Despite his apparent loyalty, he for some unknown reason does not wear a Sound headband in Part II.

While Kabuto does generally obey Orochimaru's orders, even going so far as to save Orochimaru's life at times, he is not above helping Orochimaru's enemies; for example, he heals Sakura Haruno on different occasions. When healing Sakura, Kabuto hints at an ulterior motive, saying that Akatsuki is the true enemy; Orochimaru later says something similar, pointing out that the death of more Akatsuki members means fewer enemies for him. Despite his unclear goals, Kabuto seems to be content in following Orochimaru, using the alignment to make requests for specific bodies with which to further his knowledge.

Chunin Exam
Prior to the first phase of the Chunin Exams, Kabuto befriends the members of the Rookie Nine with information on their fellow competitors. One of his remarks about the Otogakure provokes a team of Genin from that village into attacking him. Although Kabuto is able to dodge the attack fairly easily, the attack's sound-based properties make his glasses shatter and cause him to vomit.

During the second phase of the exam, Kabuto joins forces with Team 7 in an attempt to finish the phase with little hassle. When the group encounters a team of Rain Genin, Kabuto's glasses are knocked off of his face after saving Naruto from an attack. As he stares at his attackers, his eyes get a deep hue of red bloodshot. Before Kabuto can reveal the meaning of these eyes, Naruto Uzumaki defeats the Rain Genin. During the battle, Kabuto was very intrigued by Naruto astonishing stamina and chakra supplies even without the assistance of the Nine-Tailed Demon Fox. Upon completing the second test, Kabuto reunited with his teammates, Yoroi Akado and Misumi Tsurugi. Back with his team, Kabuto reports to Orochimaru what he has learned about Sasuke Uchiha, also expressing his surprise in the after-effects of the Sound Genin's earlier attack.

With Orochimaru now in a position to observe Sasuke firsthand, Kabuto forfeits prior to the preliminary matches of the Chunin Exam. While explaining to Naruto that he is fatigued, injured, and unwilling to risk his life further, Kabuto actually forfeits because he is afraid that prolonged fighting will cause him to show his true abilities, blowing his cover. After Orochimaru gathers enough of his own intelligence about Sasuke, he instructs Kabuto to kidnap Sasuke. Although he almost succeeds in accomplishing this task, Kakashi Hatake intervenes before he can finish, forcing him to flee.

During the final matches of the Chunin Exam, Kabuto disguises himself as an ANBU member and mingles with the audience. When Sasuke injures Gaara, Kabuto uses his Temple of Nirvana Technique to put the audience to sleep and signal the start of the invasion of Konoha. While he does contribute in the battle, the Konoha ninja overwhelm the invading forces, and Kabuto flees the village.

Search for Tsunade
With Orochimaru being heavily injured as a result of the failed invasion, Kabuto accompanies him in searching for Tsunade, who they hope will be able to heal him. Upon finding and in time seeming to persuade Tsunade, Kabuto notices that Tsunade's medical jutsu is filled with killing intent, and as such stops her before she can kill Orochimaru. With it clear that Tsunade won't willingly help them, Kabuto and Orochimaru lead Tsunade out to another battlefield in the fields with Kabuto aware that the other Sannin Jiraiya is nearby after learning of this during his failed attempt to assassinate Tsunade's assistant Shizune at Orochimaru's request. Kabuto then fights Tsunade in the hopes that he can force her into submission. After taking a soldier pill to boost his abilities, Kabuto is able to keep up with Tsunade and land a number of disabling attacks, though she eventually lands a crippling attack upon him. Upon recovering, Kabuto slits his wrists, drenching Tsunade in his blood and invoking her hemophobia, allowing him to land a series of unopposed attacks.

When the reinforcements for Tsunade arrive, Kabuto is pitted against Shizune, who he quickly defeats. As he returns his attention to Tsunade, Naruto Uzumaki also comes to her rescue, surprised that Kabuto is a spy for Orochimaru. While Kabuto doesn't view Naruto as much of a threat, Naruto is able to hit Kabuto with his Rasengan, doing so much damage to Kabuto that the latter is unable to fully heal. While Kabuto had managed to strike a fatal blow to Naruto's heart before the Spiraling Sphere hit him, Tsunade heals Naruto before he can die, leaving Kabuto to lie on the ground, defeated. Once Orochimaru is defeated, Kabuto escapes with his master.

Sasuke Retrieval
As Orochimaru anxiously awaits Sasuke Uchiha's arrival at their lair, Kabuto encourages him to switch to a new body while he still can, even offering his own body. Although Orochimaru rejects the offer, Kabuto finds a strong body for Orochimaru to switch to just in case. Although Kabuto's efforts seem to have been needless for a while, Orochimaru finally grows tired of waiting for Sasuke and switches to the body that Kabuto prepared. Later when Sasuke finally arrives, he sees how rude he's being to Orochimaru. He tells asks him not to be as rude even though Orochimaru's appearance has changed it's still Orochimaru. Sasuke then response with a glare and Kabuto seems to sense the power of Sasuke's chakra and backs off.

Sasuke and Sai
When Team Yamato comes to meet one of Sasori's agents, Kabuto is revealed to be that agent. Yamato, disguised as Sasori, is able to learn some things from Kabuto, though just as he is about to capture the latter Orochimaru shows up. Although it seems as though Orochimaru is about to kill Kabuto as a traitor, Kabuto cuts off the Sasori disguise's head, having intended to kill the actual Sasori under Orochimaru's orders. With his cover blown, Yamato calls to the rest of his team for assistance, and Naruto eventually starts to fight Orochimaru. At the start of the battle, Kabuto tries to attack Naruto, though he is almost instantly repelled by one of Naruto's roars.

After the battle, Kabuto joins Orochimaru and former Team Yamato member Sai in returning to their hideout, and Kabuto is tasked with leaving behind a dead body that looks like Sai to prevent anyone from following them. On the way to the hideout, Kabuto remains suspicious of the actual Sai, though his suspicions are seemingly lifted when the pursuing members of Team Yamato apprehend and restrain Sai. While showing tremendous skill in fending off his enemys' attacks, Kabuto still feels at a disadvantage and turns to Sai. Thinking Sai to be an ally, Kabuto frees Sai so that they can join efforts in defeating Team Yamato, though Sai turns on Kabuto and restrains him. Unable to escape, Kabuto is forthcoming with information, and discourages Naruto from trying to retrieve the traitorous Sasuke. Kabuto is left by himself as Team 7 searches the lair, though is at some point freed and joins Orochimaru and Sasuke when they depart.

Three-Tails Filler Arc
In this arc, Kabuto is sent out by Orochimaru (much to his disapproval) to fetch Guren. Guren attacks Kabuto as he arrives at the place where she's living, which seems to be a cave. When they return to Orochimaru's lair, Kabuto puts her in charge of pitting all the prisoners against each other for some unknown goal.

Later, Kabuto fetches another prisoner, a young boy named Yūkimaru with unusual powers. He brings the boy to a dark swamp where he uses his medical ninjutsu to forcibly release Yukimaru's strong chakra. This results in a mysterious beast momentarily emerging from the swamp. Kabuto is pleased with the results of the test.

Hunt for Uchiha
After the conclusion of the Team 10 arc, Kabuto is seen attending to a bedridden Orochimaru. Kabuto exits the room to retrieve some new medicine for him just before Sasuke breaks in and attacks Orochimaru. When Sasuke emerges from Orochimaru's room after having defeated him, Kabuto bears witness to a "recording" seen through Sasuke's eyes of Sasuke's conscious pushing Orochimaru out of his body. Before Sasuke leaves, Kabuto states to him that he will eventually come to exact revenge for Orochimaru on Sasuke, then go after Naruto. Kabuto then integrates Orochimaru's remains into his own body, which then begin to take him over; this is in an attempt to feel alive in and of himself, as he had defined himself entirely as Orochimaru's deputy, and now needs to find a new cause.

Kabuto eventually takes his data book on Akatsuki's members and, confronting the combined Team Kakashi and Team 8 (with Yamato in for the pregnant Kurenai), he reveals his attempt to integrate Orochimaru's remains into himself, which have steadily continued to consume his body; Hinata observes through her Byakugan techinque that the remains have subsumed about 30% of Kabuto's body, to include one of his eyes, giving Kabuto Orochimaru's powers. Kabuto chats with the group for a moment about his reasons for the integration before turning over the data book to Yamato. He then escapes Yamato's attempt to apprehend him and vanishes. His current whereabouts are unknown.

Abilities
Despite his official rank as a Genin, Kabuto has proven himself to be a skilled and cunning ninja, particularly because of his medical abilities; of these talents, he displayed his skills that not even Tsunade was aware of at his age. Kabuto's skills are mentioned by Orochimaru to rival that of Kakashi Hatake on more than one occasion, and has likewise been shown to be able to kill ANBU members with relative ease, even mockingly stating he could handle at least 10 ANBU members.

Despite his age, Kabuto has demonstrated tremendous skill and ingenuity in medical ninjutsu. With his extensive knowledge of medical ninjutsu and of the human body, Kabuto can quickly adjust to any damage done to his body and severely injure a person with a single chakra-infused strike to the chest, even incapacitate them if their chakra levels are low enough. He has also developed the unique ability to be able to reactivate dead cells and grow new ones, as well as being able to keep test subjects alive for much longer than is feasible. During his battle with Tsunade, she remarks that Kabuto's senses and efficiency referring to his jutsu quickness might have surpassed her own when she was in her physical prime.

While stating to have lesser skill in combat, Kabuto has shown proficient enough to fend off attacks from multiple opponents and even hold his own against the superior skill of Tsunade. His style of battle revolves mainly around his medical knowledge. He will either utilize medical ninjutsu to systematically take down his opponent at key points in the body or strike at pressure points in the form of locks to subdue his opponent.

On several occasions, Kabuto has been mentioned and shown to be a very intelligent and resourceful shinobi. His intuition has been shown great enough to even notice a harmless animal from a considerable distance. Through keen observation, Kabuto can quickly determine the situation at hand. He has proven to be crafty enough to even fool the likes of Kakashi. Even when up against a stronger opponent, he can take advantage by quickly exploiting their weakness.

Since he has integrated Orochimaru's remains' he holds Orochimaru's abilities

Quotes

 * (To Naruto) "You've thrown it all away! Dreams don't come true when you're dead!"
 * (To Orochimaru) "Orochimaru-sama." ("Lord Orochimaru." in the english dub)
 * (To Naruto) "Hehehe..., you can't beat me. You have no skills, unlike Sasuke."
 * (About Naruto) "If this kid learns how to control his chakra, he'll be unstoppable."