God Tree

The was a tree revered as a deity in ancient times. It was said to bear a fruit of great power once in a millennium, although it was forbidden to consume the fruit. The circumstances under which this prohibition came to be are unknown. Consumption of the Shinju's fruit bestows an ability upon its consumer's body to produce chakra.

Background
During an era of endless wars between mankind, before humans had even learned of the concept of chakra, they already worshiped the Shinju as the host of god. Every millennium the tree would grow a mysterious fruit, which humans were specifically instructed to never lay so much as a single finger on.

Long before the founding of the hidden villages, Kaguya Ōtsutsuki, a princess from a faraway land, came to the place of the conflict to end it. Having decided to bring peace, Kaguya breached the prohibition and ate the forbidden fruit of the Shinju, attaining god-like powers. Using her new-found power, Kaguya brought forth peace by force, causing her to be revered as the Rabbit Goddess and later as the Demon. Some time later, by means unknown, the Shinju incarnated together with Kaguya and took on a form which would come to be known as the Ten-Tails.

Personality
The Shinju was an impartial entity, completely devoid of feelings and ideals as it stayed neutral and almost ambivalent to the constant wars that were waged around it by mankind.

Abilities
Once the Infinite Tsukuyomi is cast, the user can assimilate victims of the genjutsu into the Shinju by binding them with its roots. Upon doing so, the Shinju's life force will sustain the victims' lives indefinitely, while also gradually transforming them into White Zetsu.

Chakra Fruit
Once in a millenium, the Shinju bore a single fruit, consumption of which was deemed forbidden. Upon breaking the taboo and consuming the, Kaguya Ōtsutsuki gained an enormous amount of exceptionally powerful chakra, with which she was able to single-handedly stop all the wars that plagued the lands. Kaguya was noted to be more powerful than the Sage of the Six Paths himself, with chakra that Naruto Uzumaki and Sasuke Uchiha described as being on an entirely different level than that of the Ten-Tails. By utilising the Infinite Tsukuyomi and God: Nativity of a World of Trees, it is possible to regather the chakra of all living beings throughout the entire world, assimilating them into a single being once again, thus allowing the Shinju to grow a new Chakra Fruit in place of the one Kaguya once consumed.

Trivia

 * literally means 'god tree', and its size and nature have connections to both the world tree and the tree of life, motifs that are present in several real-life religions and mythologies throughout the world.
 * In addition, the story of the Shinju bearing the forbidden fruit is very similar to the story of the Tree of the knowledge of good and evil in Abrahamic religions, in which Adam and Eve, the first humans, ate the forbidden fruit despite being told otherwise. Ultimately, while becoming wiser, it lead to their downfall by incurring the wrath of God. For disobeying Him, He forever cursed the two and their descendants. Adam's eldest son, Cain, would later murder his younger brother, Abel, in anger and jealousy following God's rejection of his offering while accepting Abel's, similar to the struggle between the two sons of the Sage of the Six Paths.
 * The wooden dragon-like entities at the base of the Shinju may be a reference to Nidhogg, a dragon or serpent who eternally chews the roots of Yggdrasil in Norse mythology. Likewise with the appearance of the Shinju, it is said that should Nidhogg finally be free of its entrapment underneath Yggdrasil, its appearance into the world beyond its roots are said to herald the coming of Ragnarök, the end of the world and ultimate battle of the gods.
 * When the Ten-Tails was recreated into a tree by Obito Uchiha in the Fourth Shinobi World War, it was initially referred to as the Shinju by Gyūki, but it was later confirmed to be a form of the Ten-Tails.
 * When Kaguya was defeated by Naruto and Sasuke, the Shinju, being one with her, was sealed by the Six Paths Chibaku Tensei in Kaguya's core dimension.