Ultra Space

Ultra Space is a several different dimensions who can be accessed in Pokémon Sun and Moon, and Pokémon Ultra Sun and Ultra Moon. Each Ultra Spaces are created especially for each Ultra Beasts.

Nihilego's Ultra Space
A dark cave, with several multicolored rocks that look like diamonds.

Kartana's Ultra Space
A forest, with Kartana-shaped leaves and people standing around.

Xurkitree's Ultra Space
A Dark cave, with electrically conductive cords in the mountains.

Buzzwole's Ultra Space
A Jungle-like area, with a erupting volcano.

Pheromosa's Ultra Space
A Rock-like world, with diamond-like rocks.

Celesteela's Ultra Sapce
A v0lcanic-like area, with several craters and magma rocks.

Necrozma's Ultra Space
A Crystallized City that had it light stole by Necrozma, with a tower-like building shining with light.

Sun and Moon
Nihilego's Ultra Space can be accessed after Nebby evolves into Solgaleo or Lunala. It is the home of many Nihilego and it's the local where Lusamine can be faced for the last time. After Lusamine is defeated, it is impossible to return to the Ultra Space.

Ultra Sun and Ultra Moon
Kartana's Ultra Space can be seen in the Pokémon Ultra Sun and Ultra Moon Detail Trailer. Xurkitree and Necrozma's Ultra Spaces can be seen in the Pokémon Ultra Sun and Ultra Moon October 4 Japanese Trailer. Buzzwole's Ultra Space can be seen in the Pokemon Ultra Sun and Ultra Moon English Trailer.

Lusamine
All her Pokémon have auras that boost the following stats by one stage:
 * Special Defense (Clefable)
 * Special Attack (Lilligant)
 * Speed (Mismagius)
 * Attack (Milotic)
 * Defense (Bewear)

Trivia

 * The Rotom Pokédex doesn't work in the Ultra Space.
 * All of Lusamine's Pokémon have (except Bewear) an angry expression instead of the normal expression.
 * If an Egg is hatched in the Ultra Space, the local where it is hatched will say Ultra Space.