/jp/ - Otaku Culture

"The Palace of the Earth Spirits (地霊殿, Chireiden) is where the heroines visit in Stage 4 of Subterranean Animism. "Chireiden" is also the Japanese title of the game.
It is a Western-style mansion with many stained glass windows on the wall placed below the Hell of Blazing Fires. It said that the Palace was constructed after the underground was separated from Hell, thus many evil spirits remain in what was the former Hell.

Satori took control of the Palace and managed it by herself with the help of her pets, keeping it relatively peaceful. Of her pets, Rin's duty is to carry corpses to the Hell of Blazing Fires for the heating of the place and Utsuho is to maintain that heat. The other pets' duties were said to be tending the garden and playing with Satori's sister, Koishi."

Source:Touhou wiki
I always thought that the pets Satori sent to play with Koishi were Orin and Okuu.Looks like Chireiden is the best mansion in Gensokyo after all since there are touhous which may only exist in our imagination.

Chireiden general I guess