Astral Duo

The Astral Duo is a collective term used to refer to Stratotheon, the legendary New Dawn Pokémon, and Cometheon, the legendary Endless Night Pokémon. As their species names suggest, Stratotheon represents day and the sun, while Cometheon represents night and the moon.

After the player defeats the Elite Four, Stratotheon/Cometheon will descend from the stars above and appear at the Temple of the Sun and Moon in Sinistra City, but only during the day in the summer/at night in the winter.