The Crystal Halls
The Crystal Halls are the fortress of Iri, the Angler, one of the Vroshir.
"Iri’s home was a palace of fluted blue crystal spread like a pair of angel’s wings. It had been carved from an astronomically large diamond, and it glittered like a rainbow in the light of the nearby star. She kept a population of about a billion living in the planet-sized inner workings of the stronghold, both to keep the vessel shielded from chaos and to take care of her collection. For in carefully sculpted displays all throughout the stronghold, she held the universe’s most rare, beautiful, unique, and powerful objects. [...] She arranged herself on a throne at the end of an audience hall carved from blue crystal. Every inch of the walls, ceiling, and floor was a masterwork sculpture, and she lounged in a throne made of living light,"
— Uncrowned (Cradle Book 7) by Will Wight