Chao System

Chao are important side characters in the Sonic the Hedgehog franchise, first debuting in Sonic Adventure on the SEGA Dreamcast. In both Adventure titles, their remakes, as well as several of the GameBoy Advance games, the Chao exist as virtual Tamagochi-esque pets for players to raise and grow, making them stronger and enabling them to compete in various races and challenges.

In Sonic Chronicles: The Dark Brotherhood and Sonic Chronicles: Remastered, the Chao function much differently, instead becoming upgradable equipment that can be equipped to the playable characters to provide a variety of effects. The "Garden" that the Chao are kept in is also very different in that the Chao do not roam around in it, instead remaining stationary.

Chao Mechanics
The Garden starts off empty, but very early on in the game, players will find an Egg. Finding and obtaining Eggs will put them in incubation. They will eventually hatch, indicated by a crunching sound effect and a twitching Chao Egg icon. When the Chao Garden is examined following this, there will be live Chao in the various nests within the garden. At which point they can be selected and equipped to a character, provided that character isn't already equipped with one. Multiple duplicates of the same Chao can be obtained, allowing the same Chao to be equipped to multiple characters at once. This also means that it's possible to go through the whole game and collect every egg, but still have some Chao left to collect.

Additionally, in the original game, the Chao could be traded between players using Local Wireless connection. Trading Chao has the benefit of allowing players to acquire new Chao from their friends, and also causes Chao to level up (to level 3), which boosts their benefits. In Remastered, due to the difficulty of implementing such a system, the leveling system is being tinkered with to potentially involve fruit that can be obtained in-game.

Lastly, there are four types of Chao in the original game:
 * Common - Common Chao are simple, two-tone normal-looking Chao and are, as the name suggest, the most common variety. They are the easiest Chao to obtain duplicates of.
 * Rare - These Chao possess one of three designs, offer stronger effects, and are considerably harder to obtain than their Common cousins. Duplicates can be found, but are very rare.
 * Unique - As the name would suggest, these Chao are one of a kind and all of them possess unique designs. Duplicates, if they even exist, are extremely rare, which says nothing for the difficulty of obtaining the Chao on their own. One such Unique Chao, Cheese, is obtained alongside Cream the Rabbit during her side quest.
 * Viral - There are only five of these guys in the game's data, and all of them resemble ninjas with differently coloured masks. They are not legitimately obtainable in the original game, as they were planned to be distributed through promotional events, and only one, Stugs, was ever actually distributed, and even then, was only released for the Japanese version of the game. They can be accessed with a cheating device, but one of them, Farfinkle, has the potential to soft-lock the game. The codes for four of them were made readily available online, but again, only for the Japanese version.