Ultra Megalopolis

Ultra Megalopolis is a city situated in Ultra Space that can be accessed from Alola through an Ultra Wormhole. The world had all of its light stolen by Necrozma. In the center of the city is Megalo Tower, a building that provides artificial light to replace the light Necrozma had taken previously and to act as a prison to keep it from escaping to other worlds. It is in the homeworld of the Ultra Recon Squad, the Ultra Beast Poipole, and its evolved form Naganadel. Poipole are also stated to not only be numerous in population, but also popular enough to be trained as first partner Pokémon for its residents.