This dimension is an alternate space where Nue resides, which Tanuki Shigaraki and Sumire Kakei referred to as the underworld (異界, ikai). The Gozu Tennō, a fūinjutsu, acts as a gateway to this dimension as well a medium through which chakra can be fed to Nue. Boruto was also able to move in and out of the dimension by subconcsiously activating his Jōgan. After the Gozu Tennō was destroyed the space began to collapse upon itself, but Sumire was able to retain a small portion of the seal.
This place is similar to an underground cave. There are several swamps with trees similar to mangroves. These are connected to each other through a network of lianas and ropes. Nue's den is inside a large, hollow trunk bound with a shimenawa.
- ↑ Boruto episode 14