Kaguya Ōtsutsuki (Kai)

Princess was the first human to use chakra after consuming the fruit of the Shinju. Subsequent to her resurrection, Kaguya became the jinchūriki of the Shinju, having used Madara's body as a medium for her own restoration.

Background
Long ago before the founding of the hidden villages, during an era of endless wars between mankind, Kaguya — who came from a far away land — decided that it was necessary for someone to attain god-like powers in order to stop the constant conflicts. For this reason, she consumed the forbidden fruit of the Shinju, gaining the ability to manipulate powerful chakra and allowing her to single-handedly put an end to all the wars that plagued the lands. Some time after this Kaguya gave birth to two sons, named Hagoromo and Hamura. They both inherited this powerful chakra and were able to manipulate it. However, the Shinju's desire to reclaim its stolen power caused the tree to assume a monstrous form, which became known as the Ten-Tails.

The furious Ten-Tails rampaged throughout the lands until Kaguya's sons defeated and sealed the beast, making Hagoromo the first jinchūriki. Hagoromo would later teach humanity the concepts of chakra, becoming revered as the Sage of the Six Paths, in an attempt to make people use chakra to connect to each other, rather than using it as a weapon as Kaguya had done.

It is said Kaguya once used the Infinite Tsukuyomi to force mankind to stop fighting.

Personality
While she desired to create peace like her sons and grandsons, Kaguya opted for a more forceful method, using her great power to make people submit to her will. As Hagoromo noted, people in time began to fear her as a demon for her methods.

Kaguya appears to care very deeply about the earth and didn't want to damage it any further opted to kill Team 7 using natural forces by manipulating the earth. She appears to be ruthless when compared to Hagoromo as she didn't hesitate to kill Naruto and Sasuke, even though she knew well Hagoromo passed his powers to them and were carrying on his will.

Appearance
A woman in possession of very delicate facial features, Kaguya also had an extremely long, sweeping light coloured hair that touched the ground. Most noticeable were two horn like protrusions which stuck out from her head — appendages inherited by both her sons. Kaguya possessed the Byakugan, and also had a third eye on the centre of her forehead that's eyelids parted vertically. Her eyebrows were cut very short — a symbol of nobility, and she wore a dark shade of lipstick on her lips and a dark shade of nail polish on her long fingernails. She wore the transitional high-collared hime-kimono which was adored with intricate lines and tomoe running down the centre and edges of the gown.

Abilities
After consuming the fruit of the Shinju, Kaguya achieved such unrivalled power that she was able to pacify the war-torn world all by herself, leading the people to worship her in fear. Hagoromo, being a legendary figure himself, praised his mother's might as superior to all others, including his own. In one portrayal of her, Kaguya was shown manipulating lightning, causing a thunder storm. Transcending her death, Kaguya was able to manifest her will into Black Zetsu, using the latter to restore her body. Upon her revival, she was also able to effortlessly turn a battlefield into a magma river, while also causing the terrain to shift and twist over itself. Her movement is shown to be extremely fast as she is capable of suddenly appearing before individuals in the blink of an eye.She can also use her extremely long hair as a makeshift weapon; capturing and tossing foes around the battlefield. Like other Shinju jinchūriki, Kaguya displayed the ability to fly.

Dōjutsu
Kaguya possesses all three of the : a combination of the Byakugan, Sharingan, and a Rinnegan. Using these dōjutsu, she was able to quell the fighting in her era and was even said to have used Infinite Tsukuyomi.

Byakugan
Kaguya wields the Byakugan in both eyes, granting her near 360° vision (with the exception of a small blind spot at the upper thoracic vertebrae), x-ray vision and the ability to see the chakra pathway system.

Sharingan and Rinnegan
Kaguya wields her Rinnegan and Sharingan together as a third eye on her forehead in the form of the Shinju's eye. As a Sharingan, it presumably grants her its basic abilities such as seeing the flow of chakra, the ability to easily recognise genjutsu and different forms of chakra, heightened powers of perception as well as the ability to copy techniques that she saw, amongst other things. The capabilities of her Rinnegan are unknown.

Chakra
According to Naruto Uzumaki, the chakra possessed by Kaguya amounts to more than even the Ten-Tails itself. Shortly thereafter, Sasuke claims that her chakra is on an entirely different level from Madara's, his own and Naruto's, while also wondering to himself how someone so powerful could exist.

Return of Madara Arc
After the Infinite Tsukuyomi was finally cast by Madara Uchiha, the man attempted to finally tie up loose ends by eliminating Naruto Uzumaki, Sasuke Uchiha, Kakashi Hatake and Sakura Haruno. When he proclaimed himself as the saviour of the world, Black Zetsu, who had been standing behind Madara prior, impaled the elder Uchiha on his hand, stating that his will was of Kaguya before expanding and moving his body over Madara's own. Madara then began to scream as the influence of Black Zetsu spread over him, before chakra began to swirl through the air towards him and be absorbed by him, swelling him up to a size multiple times greater than before.

As Sasuke and Naruto attempted to intervene, they were captured by hair-like appendages while Madara continued to grow. He eventually stopped growing, actually shrinking down to a similar size that he was originally, but Madara was no longer there, as Kaguya had taken his place. She looked on at the surroundings, noticing Naruto and Sasuke and, more important, the marks on their hands before the hair-like appendages, now made up of her actual hair, threw them back to the ground. She activated her Byakugan, noticing that the two youths had similar chakra to her sons and Hagoromo's children, before coming to the conclusion that Hagoromo had bestowed the powers to them. Kakashi asked her about her motives, and she stated that the world was her nursery and wanted no more fighting to damage it any further. She then transformed the ground into a river of lava, telling Team 7 that she will have them disappear.

Legacy
Despite Kaguya's meaningful attempts to bring forth peace, her methods only brought it about temporarily. It also inspired the people of Hagoromo's era to weaponise chakra for wars instead of using it for peace, which would include the tailed beasts being seen as nothing more than masses of powerful chakra to exploit and control. Her forceful way to achieve peace later inspired Madara Uchiha — one of her own descendants — to concoct a plan to achieve this forced peace. Madara would later succeed in casting the Infinite Tsukuyomi upon the entire shinobi world. She later manifested in Black Zetsu's will, making Black Zetsu incapacitate Madara as well as revive her.

Trivia

 * Her name and title are likely references to Princess Kaguya, the main character from, which is said to be one of the oldest Japanese legends in written record. According to the legend, Princess Kaguya wears a when she returns home to her kingdom. The name  roughly means "big bamboo tree" and is derived from an obscure passage in the second volume of the Kojiki about the genealogies of Emperor Suinin, eleventh emperor of Japan, which states that he had a consort named , the daughter of a king named ; tradition holds that these individuals served as the basis for Princess Kaguya and the old bamboo cutter in the aforementioned tale.
 * Her horn-like appendages may symbolise rabbit ears, representing her connection to the moon by evoking the moon rabbit; pop culture depictions of Princess Kaguya and the moon-folk often incorporate features like rabbit ears for this reason. This also fits with her being known as the.
 * The concept of a woman eating forbidden fruit may be based on the Bible's Book of Genesis, in which Eve ate the fruit from the tree of knowledge, which led to the original sin of mankind.

Quotes

 * (To Kakashi when asked about her objective) "This place… this earth is my precious nursery. I cannot let you damage it any more… Let us end this battle. […] Here… I shall erase you all from existence right now."