A red, European-style mansion with few windows built on a bank of Misty Lake.

It is the house where a well-known devil lives.

Since the mansion was moved from the outer world, it clashes badly with the surrounding scenery.

The residents of the mansion also have a different culture from that of most humans and youkai, and live bustling, flamboyant lives.

A large quantity of maids live and work in the mansion, and although they handle the cleaning, cooking, washing and patrolling, it is said not many of the maids are actually useful (*1).

The Scarlet Devil Mansion also has a basement, which is larger than it appears, and complicated.

There are also many rooms without windows inside, which complicate it further.

In the basement is the great library which is said to be the largest in Gensokyo.

But, it is not open to the public and no one is sure what kind of books are there (*2).

On the roof is a large clock tower with a bell, which only rings at night.

Because the mansion is only active at night.

1: Since the maids are mostly fairies, they only do what they want to do. It's quantity over quality.

2: It is said that it is full of rare magic books, Patchouli's own magic books and books from the outside world.