Zetsu

is a member of Akatsuki and Madara Uchiha's most loyal subordinate. The black half is known as, while the white half was known as.

Background
White Zetsu was among the first of the many artificial humans which were created by Madara Uchiha using a living clone of Hashirama Senju and the Demonic Statue of the Outer Path. Madara implied that Yin–Yang Release was also involved in the creation of White Zetsu and his clone siblings. Like the rest of Madara's creations, White Zetsu was tasked with intelligence gathering before he and another spiral-patterned clone were entrusted with looking after the rehabilitating Obito Uchiha. Over time, the duo became friends with the young Uchiha.

At some point when Obito's rehabilitation was near completion, White Zetsu returned to the base and alerted Obito that Kakashi Hatake and Rin were being attacked by Kirigakure shinobi. When the spiral-patterned Zetsu offered to help Obito by encasing himself around the young Uchiha in order to enable him to leave the cave, White Zetsu served to guide Obito telepathically with the information he received from his clone brothers stationed outside. When they returned to Madara, White Zetsu assured him that no one had seen them and relayed information on what had happened after Konoha reinforcements had arrived, noting that Obito didn't kill Kakashi.

When Madara was on the verge of death, he manifested his will and covered one half of White Zetsu with it, creating Black Zetsu. This in turn made the complete Zetsu partially a clone of Madara, albeit weaker. Both halves later accompanied Obito to Amegakure to locate Nagato, who had unknowingly been given Madara's Rinnegan as a child. Zetsu then accompanied Obito as he approached the orphans, introducing himself as Madara Uchiha.

Personality
Accordingly with his two differently coloured halves, Zetsu has two personalities: the original White Zetsu being carefree and playful with a habit of teasing others, traits he shares with many of his clone siblings. Black Zetsu, however, is more serious and knowledgeable, being Madara's clone. In the Japanese version of the manga, Black Zetsu only uses katakana for okurigana and furigana, while White Zetsu uses kanji and kana regularly. This is often conveyed in the anime through their different voice tones. While the two halves sometimes differ in opinions and frequently converse with each other, they are still able to function as a single entity.

Zetsu is extremely trustworthy, obedient and loyal, being entrusted with Akatsuki's secrets and knowledge of Madara's Eye of the Moon Plan, which his white half believed to be beneficial to mankind. Because of his ties to Madara, Zetsu has apparently been working with Obito for some time, originally acting as Obito's superior prior to his induction into the Akatsuki. This is furthered by White Zetsu's long history with Obito when the boy was saved by Madara during the Third Shinobi World War. Though he annoyed Obito at first, White Zetsu eventually won the boy's friendship. Like his clone, White Zetsu believed Madara was a good man at heart and saw no harm in helping Obito without Madara's permission. . Unlike White Zetsu, who was kind to his allies, Black Zetsu saw anyone beneath Madara as useless. When Obito lost the tailed beasts, Black Zetsu commented on how he was a more effective servant to Madara. He also had no qualms about using Obito's dying body as a host when he fought Kakashi and Minato, showing just how little he cared about the Uchiha's well-being, while deriding on Obito for being useless for his treason.

Zetsu's main role within Akatsuki is to function as a spy with other duties that were similar to those of a hunter-nin. He is also able to control his body and take part in the tailed beast sealing ritual simultaneously, which, in addition to being unique to him, allows him to act as a lookout while the sealing takes place. When an agent of Akatsuki, or possibly even a member, dies, Zetsu is sent to devour their bodies so as to not have their secrets revealed, which further adds to his nature as a half-plant creature. Zetsu is also the one sent to retrieve the rings of dead Akatsuki members. Due to the role he plays, Zetsu is the only member of Akatsuki to act without a partner on a regular basis. As such, he operated on his own, often moving between the different locations where the other Akatsuki members were located. This resulted in other members often reporting directly to him, rather than the figurehead leader, Pain. Zetsu would in turn report directly to Pain along with Obito, who took full control over the organisation after Nagato's death and treachery.

Appearance
Zetsu is easily distinguished by the two large venus fly-trap like extensions that envelop his head and upper body, giving him a plant-like appearance. When his extensions are open and his head is visible, it is revealed that Zetsu has short green hair, yellow eyes, and that his body has two different coloured halves. His left side is completely white, while the right side is almost entirely black. The black colour does not cover his black half's entire body, as it only extends partially down his leg, which was originally his white half's right leg. Under his Akatsuki cloak, Zetsu wears blue pants and sandals. He also has both legs wrapped in bandages, which hide the area where his right leg's black colouring merges with his white foot.

Unlike White Zetsu, who possesses human-like facial features and a proper eye, Black Zetsu shows no visible orifices at all and only his iris is visible. Black Zetsu also has white dots along the edges of his body where the two halves meet; these are not flat markings, but rather protrude from his body, like little white bumps. White Zetsu also has unusually rounded teeth. In the anime, his fingernails are painted pink and his toenails, as seen at his début, are blue. He also wears his green Akatsuki ring, which bears the kanji for, on his right little finger.

When the two halves split apart, the plant-like extensions split and hang from the waists of both. Their clothes also split in half along with them, leaving each with one pant leg or half of an Akatsuki mantle, although the two halves later discard their torn clothing. When they are emerging from the ground while split, their plant-like extensions surround the two halves in a circular pattern. The two have also demonstrated the ability to grow an additional leg to substitute for their missing half when split. After escaping capture by Chōjūrō and reshaping the black matter in his lower body into a new upper body, Black Zetsu no longer has hair.

Abilities
Zetsu, as a whole, has yet to be seen in battle. The technique he has been shown using the most is Mayfly, which allows him to merge with the ground to quickly travel to a new location, though he isn't as fast as Obito's space–time travelling. This technique is ideal for Zetsu's function as a spy, as it erases his presence as well, and is an ability that both halves, as well as White Zetsu's clones, can use. In the anime, this technique allowed a White Zetsu Army clone to bury Deidara's underground mines. In addition to functioning as a single entity by communicating through their thoughts, Zetsu's two halves are able to split apart, which allows them to act independently. While separated, the two halves can extend roots underground to communicate with each other over long distances.

Being an artificial human, White Zetsu is able to survive without food or water and does not need to carry out normal human bodily functions. He can also telepathically communicate with other clones, as long as they are within a certain range. White Zetsu has mainly been seen using support abilities and Tobi has referred to him as not being a "front line" fighter. With his Spore Technique, White Zetsu is able to plant spores on the bodies of others, which are undetectable even to sensors and Kage-level shinobi. Once activated, these spores grow into a mass around the individuals they formed on by sucking out their chakra, which restricts their movements. The spores can also use this stolen chakra to replenish an ally's chakra supply by attaching themselves to him or her. Tobi had Zetsu attach several of these spores to Sasuke Uchiha in order to monitor, and even assist him when necessary. In addition, White Zetsu is able to create and remotely communicate with near-identical copies of himself, which can be used as a special substitute by taking on the appearance and unique chakra of anyone White Zetsu touches. The clones are much weaker than the original and are therefore mainly used as decoys.

Black Zetsu has demonstrated the ability to "record" the things he sees, as he has stated that he recorded the battles between Sasuke and Itachi, and between Kisame and Killer B. He is also capable of showing these "recordings" through unknown means. Black Zetsu is also a very powerful sensor, as he was able to sense Naruto Uzumaki and Killer B as soon as they touched the ground upon leaving the Island Turtle, which was some distance away. As a manifestation of Madara's will, Black Zetsu is able to telepathically communicate with Madara. Upon being bisected and immobilised, Black Zetsu separated from the white portion of his body by seeping the black matter in his lower half into the ground and subsequently forming it into a new upper body. This new body was then able to meld with and control Obito's body, forcing him to perform the Outer Path: Samsara of Heavenly Life Technique, as well as keeping him alive for some time after, despite the technique resulting in the user's death.

Nature Transformation
Because of his origin, Zetsu's genetic material is nearly identical to that of Hashirama Senju's, as seen from Shizune and Sakura Haruno's autopsy of one of the White Zetsu clones. Because of this, Zetsu is capable of using Hashirama's Wood Release, albeit on a much weaker scale. This has been most prominently demonstrated through Black Zetsu, who has been depicted transforming parts of his body into roots for offensive purposes during battle.

Sasuke Retrieval Arc
After Sasuke and Naruto's fight at the Valley of the End, Kakashi and Pakkun appear to bring Naruto back home. As the three begin the journey back home to Konoha, Zetsu appears from the ground, having witnessed the whole battle. Later his silhouette appeared with the rest of the Akatsuki members where they discussed Orochimaru taking Sasuke Uchiha, the capturing of the Nine-Tails and the furthering of their plans.

Part II
Zetsu appears frequently throughout the series. In addition to serving his various Akatsuki duties, he watches battles of interest and then reports the outcome to the other members and eats the bodies of dead associates.

Kazekage Rescue Arc
During the extraction of the One-Tailed Shukaku, Zetsu is seen also spying on Team Guy and Team Kakashi and alerting Akatsuki. Later, he is sent to dispose the corpses of Mukade and Yura, finding Mukade a delicious meal.

After Sasori and Deidara were defeated, Zetsu and Tobi were sent to retrieve their rings, and dispose of their corpses. However, he was unable to eat Sasori due to him being a puppet, but was amazed to finally see what Sasori looked like. Tobi found Sasori's ring, wishing to take his place. Black Zetsu thought this was a bad idea, but White Zetsu thought otherwise, noting that Tobi was a good person. They later found Deidara's severed right arm and believe him dead until he arrived and proved them wrong. This caused Black Zetsu to wonder why Deidara hadn't captured Naruto Uzumaki, to which Deidara replied that he had already fulfilled his quota either way.

Hidan and Kakuzu Arc
After Hidan and Kakuzu defeated Yugito Nii, Zetsu appeared to retrieve Yugito to start the extraction. When Hidan claimed that Akatsuki was just after money like Kakuzu, Zetsu told him that when he's sad and alone, all you can count on is yourself. Zetsu is later seen sealing the Two-Tails.

Itachi Pursuit Arc
Zetsu was seen to reveal himself right after Pain's fight with Jiraiya. During the fight between Sasuke and Itachi, Zetsu watched and recorded the entire battle. When Itachi died Zetsu noted that there was something different in Itachi's fighting style during the battle. He later appeared to inform Tobi of the result of the fight and was called "aloe vera" by Naruto. White Zetsu took some offence to the name while Black Zetsu told him to ignore him. He then led Tobi to where Itachi and Sasuke were.

Tsuchigumo Kinjutsu Arc
In the anime, Zetsu was present alongside the other Akatsuki members when they extracted the Six-Tails from Utakata.

Invasion of Pain Arc
After the battle between the Uchiha brothers, Tobi met with Zetsu on a bridge where they discussed the fact that Itachi — who had been hampering their plans — was dead and Zetsu enquired what Tobi's next move would be.

Five Kage Summit Arc
After Itachi's defeat and Sasuke's recruitment, Zetsu took a more active role in Tobi's ongoing plans as now there were only three Akatsuki members left, marvelling at the effort that went into getting Sasuke to work with Akatsuki. He was later revealed to have watched the entire fight between Pain and Naruto Uzumaki, and appeared next to Tobi as he argued with Sasuke about what his next objective was. There he revealed that Konoha had already been destroyed. When asked by Tobi, he revealed that Danzō had been named the acting Sixth Hokage. He then proceeded to explain the outcome of the battle between Pain and Naruto. When Taka agreed to go to the Kage Summit, Zetsu revealed his ability to split in half, and White Zetsu proceeded to lead Sasuke and his team to the Kage Summit while Black Zetsu remained behind and discussed with Tobi the fact that they might lose control over Sasuke and would therefore lose their last chance to have someone sync with the Demonic Statue of the Outer Path. Tobi declared that he was tired of hiding, and explained that they needed to speed up the "Eye of the Moon Plan".

White Zetsu stayed with Taka in the Land of Iron, observing the meeting of the Five Kage and trying to figure out a way to successfully assassinate Danzō. After identifying Danzō, White Zetsu managed to slip away from Taka unnoticed. At that time, Black Zetsu was in the Land of Iron with Tobi, who instructed him to "begin". White Zetsu then emerged in the conference room, telling the five Kage that Sasuke was somewhere around. After revealing himself, the Fourth Raikage grabbed the white Zetsu's neck, asked him about the whereabouts of Sasuke, and threatened to use force. Zetsu mockingly replied that he would give a hint, which prompted the Raikage, angered, to tighten his grip on Zetsu's neck. With his neck snapped, the White Zetsu collapsed on the floor and was presumed to be dead by everyone in the vicinity.

After Sasuke had been struck by the Fifth Mizukage's Boil Release: Skilled Mist Technique, Zetsu's Spore Technique, which had secretly been implanted on everyone in the meeting hall before the Raikage's attack, activated. The spores leached some of the Mizukage's chakra while binding the samurai guards, Mifune, Ōnoki and everyone else. Black Zetsu commented on how foolish the five Kage were, as they had failed to detect his technique. One of the spores then jumped onto Sasuke and gave him the absorbed chakra, allowing him to use an arm of Susanoo to escape from the Mizukage. The spores were later successfully neutralised by everyone present at the time of their release.

After Naruto and Sasuke clash, the aftermath of which sends Sasuke hurtling towards a wall, a clone of White Zetsu appears and wraps himself around Sasuke to cushion the blow. Revealing that Tobi had told him to keep an eye on Sasuke, the clone contacts the real White Zetsu, who alerts Tobi. Upon Tobi's arrival, the White Zetsu clone, prepared to fight and capture Naruto, created several more copies of himself. Before he could engage in combat however, Tobi tells him not to as he wasn't a 'front line' fighter, and instead gives him the task of checking up on Kisame and rejoining with Black Zetsu.

White Zetsu and Black Zetsu meet up at the site of Killer B and Kisame's battle only to reveal that Kisame's decapitated body was actually one of White Zetsu's shape-shifting clones. It is then revealed that Kisame, by having the clone fake his death, was then able to infiltrate Kumogakure while inside Samehada which was being carried back to Kumogakure by Killer B who intended to use it as his own weapon. Black Zetsu then stated that it was their feeding time and that they should merge once again.

Confining the Jinchūriki Arc
Upon Tobi's return to the base, Zetsu, now with his halves rejoined, informed him that the scroll with information from Kisame Hoshigaki sent through his messenger shark had arrived. He also noted that everything seemed to be going in their favour. Kabuto mentioned that he could make Zetsu stronger and that he was the key to fighting the shinobi forces.

Tobi promised to give him "one Zetsu" if Kabuto captured the Nine-Tails. Later, Tobi revealed his army comprised of one hundred thousand clones of White Zetsu to Kabuto, which he would use to fight the numbers of the Allied Shinobi Forces.

Shinobi World War Arc
Supervising Sasuke's recovery, Zetsu told him to be patient when asked if his bandages could be removed, remarking that when he did regain his sight it would be to a different world. As the Fourth Shinobi World War commenced, Black Zetsu departed to enact Tobi's plan to capture the daimyō and hold them hostage to force the opposition to bring Naruto and Killer B to them. White Zetsu, on the other hand, was left behind to make sure Kabuto could not abduct Sasuke during the confusion of war. Later, after Kabuto demonstrated the Summoning: Impure World Reincarnation technique, Black Zetsu emerged from the ground near Tobi. When asked if White Zetsu's spores had been placed on Kabuto's body, Black Zetsu confirmed, before being instructed to carry out his assigned tasks.

Emerging from the ground near the daimyō's hideout, Black Zetsu infiltrated the structure, despite alerting the enemy to his presence. However, upon discovering the daimyō's absence, Black Zetsu retreated and declared that they shouldn't underestimate his capabilities, as he was a part of the very land itself. Later locating his desired targets, he was instead obstructed by Mei Terumī and her squad, but sensing the Eight and Nine-Tails' chakra while confronting the team, he immediately communicated this to Tobi via White Zetsu. Told that the daimyō were no longer necessary with their quarry now in the open, Black Zetsu was ordered to continue with his guerilla tactics against the Mizukage's team to keep them from regrouping with the rest of their forces. The fight continued throughout the night.

On the second day of the war, White Zetsu was used as a test subject for Sasuke's new eyes and impaled by a blade formed from the black flames of Amaterasu, which was wielded by the youth's Susanoo, and was subsequently incinerated.

Continuing to battle with Mei and her squad, Black Zetsu observed the arrival of Naruto's shadow clone to their location, who then proceeded to crash into a tree beside him. Growing roots from portions of his body whilst fighting, he used them to trip Naruto and avoid his Rasenshuriken, only to be bisected from behind by the enlarged blade of Chōjūrō's Hiramekarei. Immobilised, Black Zetsu wondered how the sword grew to such a size in an instant and was then sliced in half and pinned to the ground by Chōjūrō's blade as the Mizukage departed. Having been reincarnated, Madara telepathically communicates with Black Zetsu, ordering him to keep watch on Obito until after his "playing" with the Five Kage is done. Subsequently, Black Zetsu seeps into the ground, escaping.

Return of Madara Arc
With Obito weakened after the tailed beasts were extracted from him, Madara enacted his trump card. With this, Black Zetsu suddenly emerged from underground and restrained him. As he began to meld with half of Obito's body, Madara was able to force Obito into using the Outer Path: Samsara of Heavenly Life Technique. Apologising as this all unfolded, Black Zetsu noted that from the start, this was his sole purpose. With Madara's revival a success, Black Zetsu attempts to retrieve Madara's Rinnegan eye from Obito until Minato and Kakashi intervene. Black Zetsu once more melds with Obito's body, using the Uchiha's body to battle his former team and noting that his merger was the only thing keeping Obito live. While both sides were at a stalemate, the Demonic Statue of the Outer Path emerged from Obito's artificial body, quickly being teleported. Afterwards, Black Zetsu again attempted to take the left Rinnegan. Obito, managing to resist Black Zetsu's control of his hand, told Kakashi to destroy the Rinnegan. Black Zetsu, realising what the summoning of the Demonic Statue meant, informed his enemies that Madara has regained his right Rinnegan.

Creation and Conception
In Naruto Hiden: Sha no Sho Character Official Data Book, Kishimoto revealed that he had originally planned for Akatsuki to be a group of monsters, "with almost no human characteristics", and that Zetsu's design was modelled after an insectivorous plant. He also stated that he had decided to make Zetsu half black and half white to "better show his split personality".

Trivia

 * According to the databook(s):
 * Zetsu's hobby is observing unique shinobi.
 * Zetsu wishes to fight people who are likely to leave behind a corpse that will make a good meal.
 * Zetsu's favourite food is "chewy" people, while his least favourites are konnyaku and jelly.
 * Zetsu's favourite phrase is, which roughly means "The only one you can count on is yourself".
 * Wherever Tobi is, Zetsu is never far behind.
 * Tobi made a deal with Kabuto, in that he would give him "one Zetsu", provided he were to capture the Nine-Tails.
 * Zetsu and the White Zetsu Army clones are not dissimilar to the legends told of the mandrake plant used to create artificial men.
 * Zetsu is the only member of Akatsuki that has yet to make a playable appearance in any video game.

Quotes

 * (To Tobi about joining Akatsuki) Black Zetsu: "Idiot, it's not that simple." White Zetsu: "It'll be all right, after all, Tobi is a good boy."
 * (To Hidan) White Zetsu: "Sorrow begets solitude…" Black Zetsu: "…The only thing you can have faith in is yourself."
 * Black Zetsu: "An expert with a pebble can still beat a novice with a shuriken."
 * Black Zetsu: "I can't believe no one noticed my Spore Technique… The Five Kage are a bunch of fools!"
 * Black Zetsu: "They underestimate Black Zetsu's powers… I am the land itself!"
 * (To Obito) Black Zetsu: "No hard feelings, Obito… This has always been my one and only purpose…"
 * (To Minato and Kakashi) Black Zetsu: "I'm Madara's will. I'll eliminate whoever stands in his way."