The unidentified world (知れぬ世界, shirenu sekai) is a planet that exists in an unknown region of space, which was destroyed by Momoshiki Ōtsutsuki for the sake of harvesting chakra fruit from one of its God Trees. After learning of the unreported abnormal space curvature of Kaguya's world, Earth, he orders Kinshiki to make preparations for them to travel there.
In the novelisation, it is described as a planet with russet-coloured terrain, bathed in the synchrotron radiation of a dying red sun, which produces its brilliant auroras. Rather than an apparent orchard for God Trees, the stump of the God Tree that Momoshiki harvested is located in the heart of a ruined metropolis brimming with corpses, and it notes that Momoshiki effortlessly destroyed the world, and its entire population, for no other reason than to harvest its chakra fruit. Momoshiki describes this fruit as "adequate" for a world with such a "low civilisation level", but later deems it a "worthless heap" when considering the abundance of chakra that could exist on a world whose inhabitants were able to defeat Kaguya.
In the anime it is depicted as a barren world with other nearby planets, nebulae, and asteroid fields in its solar system clearly visible in the night sky, as well as localised auroras. It appears to act as an orchard for the Ōtsutsuki clan, with several immature God Trees dotting the landscape in addition to the massive stump of the one Momoshiki harvested. Momoshiki describes the fruit as "adequate".