Princess Peach's Castle/Castle Archives

Not to be confused with the library seen in His Domain.

The Castle Archives is an anomalous part of Princess Peach’s Castle found in some personalized copies of Super Mario 64. It is a vast library with several books laid out that explain how to find secrets in the game, mostly those of an anomalous nature. They also seem to allude to a fundamental part of how the Personalization A.I. works. The most common way to find the Castle Archives is by interacting with a bookcase somewhere in the castle, usually an anomalous floor such as Floor 2B, causing it to move and reveal the Archives. Some say the Book on Bad can be found in the Castle Archives or is required to unlock it.

Description
The Castle Archives is typically a large, open, square room with several bookcases and tables with books laid out that can be interacted with that contain several hints to missions in courses that the player hasn’t collected upon first entering the Castle Archives, hidden collectibles such as the Eternal Star, how to access hidden levels or parts of the castle, random stories you’d expect to find in a book, and most notably, simply explaining concepts such as the Cape Feather, a forest, and the Koopalings. The Castle Archives has also been said to be shaped an irregular way, such as a winding hallway somewhat in an S or C shape.

The Archives can also contain stars on its own, usually hinted at by books as well. The most common of these is making another bookcase reveal a hidden room with the star hidden behind it, or by interacting with certain books in a specific order, usually based on the color of their covers. However, some have said there is an extra room with massive books that the player has to navigate, with papers acting similarly to the carpets seen in Rainbow Ride.

Another notable aspect of the Castle Archives is that some say the Book on Bad can be found and read in this area, usually detailing Bowser’s advances through Princess Peach’s Castle and the levels of the game, explaining how to get to Bowser in the Sky or the copy’s final level if it’s different, or being a guide on how to be evil. The Book on Bad can also supposedly be picked up and be used to access other areas such as Bowser’s Domain, but this is rarely mentioned in documentation of the Castle Archives.

Faraway Fairy Tale
As this level’s name suggests, it’s a level taking place in a fairy tale, found by jumping into one of the Castle Archive’s books. The level itself is described as a bright green meadow with a wizard’s tower and multiple rainbows. The level’s enemies are usually reskins of regular Super Mario 64 enemies to appear similar to fantasy characters, such as dragon Koopas or knight Goombas.

The level’s missions involve climbing a rainbow, reaching the top of the wizard tower, or slaying a unique dragon boss, which is most similar to Bowser but with an entirely unique model. The dragon is also reportedly buggy, likely due to being a unique boss fight potentially entirely made by the A.I. or the animations from Bowser not being created for this boss fight.

Monochrome Meadow
Not to be confused with the Monochrome Meadow seen in Wow! Waluigi.

Monochrome Meadow is a grayscale level, fittingly with grayscale variants of enemies and objects, sometimes even including Mario. Those who have encountered the level say that the books in the Castle Archives leading up to the level are all about sad stories and gradually lose color before the player reaches the pure white room leading to Monochrome Meadow. The level’s theme is commonly a slower version of Bob-omb Battlefield’s theme.

The level is much more basic compared to Faraway Fairy Tale, but it does have a unique cavern sub-area and a collectible known as the Monochrome Medal, seemingly unrelated to the other anomalous medals. The cave is also grayscale, unlike the other cave levels in Super Mario 64. It is unknown if the developers were just trying to make a regular gray stone cave or if this was intentional to fit the monochrome theme of this level.

The missions in this level are also basic, typically consisting of climbing a large flower, jumping to some clouds from the flower, occasionally requiring the player to Backwards Long Jump to fling themselves over to the star, exploring the cavern, collecting 8 red coins, defeating enough enemies in a certain area, or somehow restoring color to the level.

Bowser in the Colorless Canyon
This level is, as the name suggests, a Bowser level taking place in a grayscale canyon with the same effects as Monochrome Meadow. It usually appears in the same area of the Castle Archives as Monochrome Meadow, requiring the Monochrome Medal to enter. The level usually takes place towards the top of the canyon, with a seemingly bottomless pit beneath the player.

This Bowser level is unique, as some say Bowser does not appear at the end of the level, instead being replaced by some other boss, usually a monochrome version of some boss, or oddly enough, a team of Piranha Plants, similarly to the mission in Tiny-Huge Island. This may be due to the Castle Archives not being a main floor, meaning that this level is entirely optional. In the actual game, some say that the boss’ dialogue says that Bowser was too busy fortifying another level, usually the next Bowser level the player has to clear.

Upon defeating the boss, most say that they typically drop a Power Star, or a key to a hidden room mentioned by a book in the Archives, usually containing a Power Star and even more hints for the player, but some say the boss drops the Book on Bad if it was not already in the copy, especially if it is used as a collectible. There is also an 8 red coins star in the level, and some say that if you manage to get to the actual top of the ravine, there is an extra star found on the top of the level.

Theorizing
The Castle Archives was likely a way for the developers to give younger players an easier experience in the game back when it was much more expansive, with the levels inside of it meant to be an easy way to get Power Stars. However, considering the anomalous floors the Castle Archives appear on usually being later in the game’s progression, this theory has been contested, though it might just be where the Personalization A.I. relocates it to.

Another theory is that the Castle Archives was a literal library for the Personalization A.I. Those who believe this theory say that it would be a physical way for the A.I. to keep track of its changes, such as new levels and new missions, and also contain information for the A.I. to use to create levels and missions and teach it how to write dialogue, explaining the random stories and descriptions of locations or power-ups in the Super Mario Bros. franchise. This would mean that the Castle Archives were never meant to be seen, instead being introduced into the game by the A.I., with the levels also likely being made by the A.I. through processes like Dynamic Level Arrangement, explaining their basic nature.