The Mansion, introduced during the Ratboy's Nightmare Update, is a location that players can explore in The Nightmare. The Mansion is a massive abandoned mansion housing many hallways, rooms, storages, and closets that connects many areas of The Nightmare together. acts as the starting point in the player's adventures through the Nightmare, linking and connecting to multiple places as soon as the players get their hands on a Mansion Key, which includes The Grand Hall, The Old Mansion, Inside, Meeting Place, and the Fish Hall.
Like all zones, it is overrun by bizarre and terrifying creatures that roam its halls and rooms, as well as collectibles of the nightmare being found in selective areas of the zone. Some of these mobs include but are not limited to the Spikers and the Corrupted Onyx Knight.
Regarding the monsters that roam The Mansion, certain doors can only be accessible after deciphering codes and/or acquiring keys or cards to open it. Most of The Mansion's areas can only be accessed by players with the Mansion Key, otherwise, the players will get nowhere into the Nightmare.
With the Mansion Key, players can unlock many places in The Mansion, such as another route to get to The Grand Hall, a library-room where the riddles can be found at, a Guttermouth Cell room, and so forth.
- It is sometimes referred to as the Nightmare Mansion by some players.
- The Running Man is one of the most common collectibles seen in the zone.
- The Yellow, Blue, Purple, and Pink Doors can be found in The Mansion in their own respective areas.