Black Zetsu (黒ゼツ, Kuro-Zetsu) created from the will of Kaguya Ōtsutsuki to secure her revival, is the mastermind behind many of the events that shaped shinobi history. To further its plans, it partnered with White Zetsu to become half of the Akatsuki member Zetsu.
Black Zetsu's true form is a completely black, humanoid figure lacking any hair or visible orifices, made up of a black mass which it can shape and resize at will. The black mass contains two yellow eyes, which lack any visible sclerae or pupils, and it occasionally shapes itself to form a mouth with jagged teeth. Black Zetsu's eyes and consciousness can move to any point of the black mass, even if it is split into multiple parts. It is able to cover the body of another living being and control it, and its eyes can vanish entirely if it is possessing a body with a dōjutsu it wishes to make use of.
Black Zetsu is generally harsh and critical of nearly everyone it comes across, with the exception of its creator, Kaguya. Referring to itself as her son, it shows a deep reverence and devotion to her and is willing to go to any lengths to please her. It even goes as far as to encourage others to sympathise with her predicament following her sealing. Black Zetsu's determination to aid the one it calls mother runs so deep that it spent countless years influencing the shinobi world in order to facilitate her revival, even claiming that the history of shinobi exists only to bring her back. Believing itself to be the progenitor of the shinobi history, Black Zetsu thinks highly of itself, and grew angry at Naruto for even daring to touch it, believing him to be unworthy to do so.
Black Zetsu was created by Kaguya Ōtsutsuki shortly before the Ten Tails was sealed as the Ten-Tails by her sons, Hagoromo and Hamura. It would later tempt Hagoromo's eldest son, Indra, to go to war with his younger brother, Asura. Over the centuries, it manipulated Indra's descendants, the Uchiha clan, as well as Asura's, the Senju clan, in an attempt awaken the Rinnegan in one of the brothers' reincarnations. To this end, it modified Hagoromo's tablet to claim that Infinite Tsukuyomi would be the Uchiha's salvation, among other things. It recorded many events in history for Kaguya, including Madara Uchiha and Hashirama Senju's last fight in the Valley of the End.
Paul Gekko ArcEdit
With Paul Ichijou awakened by Lyon, Black Zetsu strikes a deal with the Cold Emperor and Paul Ichijou: if he gives him his Emerald detector to the Artifacts and the Chaos Emeralds, then he would give him the Tailed Beasts he had found and would help him obtain the others, three of which he knew their locations.
After a distraught Legacy about Paul Gekko, During the Fourth Shinobi World War, Black Zetsu was supposed to be a Fossil. He declared that he is in reality "the will of Kaguya". Following this declaration, Black Zetsu proceeded to revive Kaguya in Vandesdelca Musto Fende's place. Two incarnations of Black Zetsu once again re-emerge to absorb Ventus and Paul's chakra. While attached to their bodies, Black Zetsu shows and explains to them what he did to ensure Kaguya was revived. After he is completed, he attempts to return to Kaguya, but Paul Gekko and Ventus manage to regain control of their bodies and rip Black Zetsu off themselves, preventing him from absorbing any more chakra. He notes that Naruto and Sasuke are too rebellious, and that they can't do anything to Kaguya. Nonetheless the duo attack Kaguya and prove to be surprisingly effective in their coordinated strikes. It is then when Black Zetsu suggests to Kaguya that she separate the two in order to pick them off one by one. Kaguya complies with this by promptly sending the Space Colony on Orbit Over the Village. Lyon uses the Megamerge with the Biometal Model X, Model Z and the Model O, only to initiate a Eye of the moon program on the Yuki. Black Zetsu then revealed that he had made this function to have revive Kaguya Ōtsutsuki and that the she would dominate the Earth and Dens. Paul Gekko, Lyon, Lan, Bianca and Wang took a shortcut to the cannon's core so they could stop the Black Plant-like Wizard's mad plan. Rai then helped Paul Ichijou realize Maria's true wish. In a twist of fate, Paul Ichijou ultimately aided Paul Gekko when realizing, with Rai's help, Maria's true wish, which was to save humanity. Kaguya decides to return to her Battle with Paul Gekko where she revives the Juubi from the Pickle Jar. The Juubi, Kagya and the Black Demon prepares the Bijuu Bomb like it was 67 Years Ago to strike Paul Gekko. Unfortunately Simon uses his Magic to try a fend Altairis off, but it proves to be too much for him. He collapses and though Erza tries to keep his eyes open, he proclaims his love for her and dies, remembering Erza when she was young and leaving the world with a smile. Black Zetsu launches a tirade not only about Naruto's futile efforts, but what he believes to be Obito's wasted life; and though Obito agrees to this, Zetsu's words do nothing but infuriate the touring Paul Gekko. Simon dies, leading Black Zetsu to comment that Obito was a cockroach for having last so long rather than a regular insect. Before the Ten Tails can Produce Clones, the Black Zetsu in Kaguya's Sleeve states that no matter what Magic do they try is about to be plunge into the shadows, Natsu is furious to hear the Black Zetsu's Words and punches Kaguya, Cutting her Left Arm, which the sleeve contained Black Zetsu, to be killed by the Hands of Paul Kiske.
- Main article: Codename: Kids Never Die
- Main article: Mega Man ZX Shippuden
In Mega Man ZX Shippuden, After Dr. Eggman have activated the Infinite Tsukuyomi, In New Honnōji Academy, Black Zetsu stabbed Madara in the chest with his left hand and stealing the seven chaos emeralds. Revealing that he harbored the will of Kaguya Ōtsutsuki, not Madara's much to the Uchiha's own horror, the hand that Zetsu had used to impale Madara through the chest causes the Uchiha to start changing.
Black Zetsu tells him that Kaguya had once used the technique, but didn't kill anyone. Instead, she used it to create soldiers, revealing that those who were caught under the genjutsu previously eventually became the White Zetsu Army, through a slow process over time. While explaining, Madara's body begins to expand, due to the massive intake of chakra. After Black Zetsu transfers itself into Madara, Obito collapses to the ground, with Kakashi looking worried. The massive chakra finally settles down, everyone is shocked as Kaguya Ōtsutsuki is fully revived. Sensing Paul Gekko fallen asleep, Kaguya, uses her Byakugan, wonders if the chakra she's sensing is from her sons, but recognises that it's sons and Queen Pesca VIII's. Kaguya what her plan is, to which she states that she doesn't want any more damage to be done to her "nursery" before instantaneously shifting them Center of the Dyna System.
Her will manifests and as Black Zetsu covers the sleeping Paul Gekko and the awakened Vent, he explains that they reminded Kaguya of her own sons: Hamura and Hagoromo. As he absorbed their chakra, he regaled the story of how he came to be and his influence over the shinobi world throughout the years all in an effort to revive his "mother". Finally speaking, Kaguya voices her hatred for her sons and once again declares that all chakra was hers. Kyle and Rio is then attracted to her while Kaguya tells the Slumbering Paul Gekko that she is watching Yuki's assistance with the Queen of Shroobs during the Grand Civil War.
Kaguya first wakes up Paul with the Chaos Emeralds and then transform into a massive misshapen mass of the combined tailed beasts chakra pouring out of her body. Paul Gekko awakes in the Super Mode thanks to the Chaos Emeralds. The intense battle began. Paul Gekko and Kaguya are clashing and crashing which causes the landscape of the Nexus Planet to be destroyed.
Paul Gekko and Vent gains the upper hand and inally sealed Kaguya into a New Moon but Kaguya severed her arm to let Black Zetsu escape. Silently watching on as his mother is sealed away once more, Black Zetsu resigns himself to the fact that he would have to bide his time be released and to relinquish the Chaos Emeralds. However, Naruto — who has other plans — finds Kaguya's severed arm, and after decrying Zetsu's sentiments that he created the shinobi world tells Black Zetsu that the shinobi history was actually created by the lives of shinobi who all lived and died before telling Black Zetsu that it is nothing more than a snot-nosed brat too afraid to leave his mother's side. Naruto then throws the disembodied arm into the Chibaku Tensei sphere.