Zetsu is a member of the Akatsuki and his ability to fuse inanimate objects makes him the ideal information gatherer and observer for the group.
Zetsu first appeared after the battle between Naruto and Sasuke in the Valley of End. He reported directly towards the Akatsuki Leader Pain but is really reporting to Tobi, informing him on the status of Sasuke Uchiha.Zetsu later appeared with the rest of Akatsuki in the Land of Sand. While sealing Gaara's Ichibi, Zetsu informed Akatsuki that the Leaf ninja were closing in and so Pein created clones of Itachi and Kisame to stop them. He was then ordered to "dispose" of the bodies of the Itachi and Kisame impostors.( It should also be know that he is a cannibal and this is one of his ways of getting rid of bodys)
He is seen after the battle between Chiyo, Sakura, and Sasori, trying to find Sasori's ring. There, he finds Tobi with the ring and asking if he could join. After some arguing with himself, he allowed Tobi to join.He was then seen after the battle of Deidara and Team 7. Here he recovered Deidara's ring, but discovered that Deidara was still alive.Zetsu is then seen after Pein's battle with Jiraiya. Pein explains that Jiraiya showed up out of nowhere shortly after Madara ordered him to capture Naruto. One side of Zetsu asked if he could go with him, but the other side wanted to go watch Sasuke's and Itachi's fight instead.
Zetsu first appeared after the battle between Naruto and Sasuke in the Valley of End. He reported directly towards the Akatsuki Leader, informing him on the status of Sasuke Uchiha.
Zetsu later appeared with the rest of Akatsuki in the Land of Sand. While sealing Gaara's Ichibi, Zetsu informed Akatsuki that the Leaf ninja were closing in and so Pein created clones of Itachi and Kisame to stop them. He was then ordered to "dispose" of the bodies of the Itachi and Kisame impostors.
He's seen after the battle between Chiyo, Sakura, and Sasori, trying to find Sasori's ring. There, he found his subordinate Tobi with the ring and asking if he could join. After some arguing with himself, he allowed Tobi to join.
He was then seen after the battle of Deidara and Team 7. Here, he recovered Deidara's ring, but discovered that Deidara was still alive.
Zetsu is then seen after Pein's battle with Jiraiya. Pein explains that Jiraiya showed up out of nowhere shortly after Madara ordered him to capture Naruto. One side of Zetsu asked if he could go with him, but the other side wanted to go watch Sasuke's and Itachi's fight instead.
After Itachi's defeat and Sasuke's recruitment, Zetsu took a more active role in Madara's ongoing plans as now there are only three Akatsuki members left, marveling 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 the white half proceeded to lead Sasuke and his team to the Kage Summit while the black half remained behind and discussed with Madara 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. Madara declared that he was tired of hiding, and explained that they need to speed up the "Eye of the Moon Plan".
The white half stayed with Taka, currently 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, the white half managed to leave Taka and slip into the conference room, telling the five Kage that Sasuke was somewhere around. At that time the black half was with Madara, both hidden in the Land of Iron and received the instruction to "begin".
After revealing himself, the Fourth Raikage grabbed the white Zetsu's neck, asking him the whereabouts ofSasuke, and threatened to use force. Zetsu mockingly replied that he would give a hint. The Raikage, angered, tightened his grip on Zetsu's neck. White Zetsu collapsed on the floor, and everyone there presumed that he died. After Sasuke had been struck by the Fifth Mizukage's Boil Release: Skilled Mist Technique, Zetsu used some kind of Spore Technique, which was secretly implanted in everyone in the meeting hall before the Raikage's attack. The spores leeched some of the chakra of the Mizukage while binding the samurai guards, Mifune, Ōnoki and everyone else. His black half comments on the five Kage being fools, as they failed to detect his spore jutsu. One of the spores then jumped onto Sasuke, but instead gave him the absorbed chakra, allowing him to use an arm of Susanoo to escape from the Mizukage. Everybody is able to remove the spore technique thanks to Kankurō's puppet strings, with the exception of the Five Kage and Akatsuchi (they removed it themselves). Mifune then stabs one of Zetsu's clones through the head. The spores had also been implanted within Kurotsuchi, Ao,Danzō, Fū, and Torune, all of whom had left the meeting hall for various reasons, but they had managed to get the parasitic technique off of themselves.
Zetsu's white half reveals after Sasuke and Naruto clash that Madara told him to keep an eye on Sasuke. Upon calling Madara back, white Zetsu was prepared to fight and capture Naruto while he demonstrated an ability to create several copies of his white half. Before he could engage in combat however Madara tells him not to as he wasn't a 'front line' fighter, and instead gives him the task of checking up on Kisame and to rejoin with his black half.
White Zetsu and his Black half met up at the site of Killer Bee and Kisame's battle only to reveal that Kisame's decapitated body was actually one of their shape-shifting clones. The real Kisame, by having the clone fake his death, was then able to infiltrate Kumogakure while inside his sword, Samehada. The sword itself is being carried on the back of Killer Bee who plans to use it as his new weapon. Black Zetsu then says that it's their feeding time and they should rejoin.
Upon Madara's return to the base, Zetsu, now with his halves rejoined, informs 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 favor. Kabuto mentioned he could make Zetsu stronger and that he was the key to fighting the shinobi forces. Madara promised to give him "one Zetsu" if Kabuto captures the Nine-Tails. Later, Madara revealed to Kabuto a hundred thousand clones of white Zetsu, which will be used to match the numbers of the Allied Shinobi Forces.
The original Zetsu was left at the headquarters to keep an eye on Sasuke while he's recovering in order to prevent Kabuto from capturing him during the war. He tells Sasuke to be patient when he asks whether or not it was time to remove his bandages and that when he does he would see a different world; stating that things have gotten fun. Later Zetsu's black half arrives near Madara who inquires if White Zetsu's spores have already attached themselves to Kabuto. When Black Zetsu affirms this Madara then instructs him to carry on with his own assigned tasks.
Zetsu is still a mystery, however he frequently uses the "Leech All Creation: Attack Prevention" technique, which allows him to fuse with anything that does not move, such as trees, rocks, and the ground, allowing him to travel great distances very quickly. Zetsu is also able to move during the Sealing ritual, a skill which he solely holds. This makes him a lookout during the ritual. He also functions as a Hunter-nin, devouring the bodies of victims.
Zetsu has also shown the ability to split in two, so that his two personalities can act independently. He is also able to use a time-delayed spore jutsu to grow into a mushy mass around several individuals at once, thereby sucking their chakra out, and can even use it to replenish another persons' chakra. Zetsu's white half has also shown the ability to create multiple copies of himself. Zetsu can create a special clone which can simulate the appearance anyone Zetsu has ever touched down to their chakra, but it is much weaker than the original person, and therefore mostly only useful as a diversion and decoy.