Long ago, the very land was ravaged by bloody, incessant war. It was from the blood of the fallen warriors that fought on the plagued land that a tree of immeasurable power rose. This was the Divine Tree, Shinju. Every millennium, this tree bore a sacred and powerful fruit that humans were instructed to never touch. But, there was one that defied this unwritten law that was put into place by Shinju itself. It was a princess by the name of Kaguya Otsutsuki that wished to cure the plagued land of war. She defied the taboo and consumed the tree's sacred fruit. Upon consumption, a raw, powerful essence that was said to be the power of god flowed through her mortal body. With this power, she alone liberated the ever warring land and ushered in a long awaited era of peace. As such, she became heralded as the Rabbit goddess. In time, she became pregnant with children.
These children inherited Kaguya's godlike powers, the strange energy that became known as chakra, and they spread it to the rest of the world. This gave birth to a more powerful warrior, the likes of which the world had never seen, the ninja. Ultimately, Kaguya became the progenitor of an advanced weapon; what she created was a higher form of war. The day Kaguya ate the fruit was the day she consigned the world to unimaginable pain; a pain far greater than experienced during the endless war, simply because she brought the warrior into being. The ninja: a cursed warrior that utilizes chakra to defend his ideals and that which he cherishes. Ninja give everything they are to lose everything they have. Simply put: pain, sorrow, despair, loneliness; this is the fate of a ninja.