Chaos Chao are very special chao that can only be obtained under special circumstances.
Chaos Chao are near, if not the most, coveted type of Chao in the game. They are immortal, meaning they will not die, have very unique appearances, a unique Ball above their heads, and since they are immortal they have no need to mate with other Chao. The Neutral, or Light Chaos Chao will have a glowing ball. The Hero, or Angel Chaos Chao will have a glowing, translucent Halo. The Devil Chaos Chao will have a flame similar to that given by the Half-Fish.
Well, let's start with the basics. To start with, your Chao needs to have reincarnated at least twice. In the doctor's room this is called transformations. To have a Chao reincarnate, you must treat it with care and love. It's Happiness must be at a certain point for it to reincarnate. If one whistles and the Chao starts running towards them, this is a sure sign it will reincarnate.
Each time it does reincarnate, it will keep it's grades, 10% of its stat total, and all of it's stats will revert back to level one. It will retain its rewards and lessons it learned in past lives. Additionally, it will keep its eye traits if it was a Dark Chao in it's past life. It's alignment will reset however.
These are also the steps to obtain a Chaos Chao. They apply to both Sonic Adventure 2 for the Dreamcast and Sonic Adventure 2: Battle for the Gamecube.
- Your Chao must have reincarnated at least twice (as stated prior). So it needs to be on its third life or higher.
- Your Chao Must Have At Least 50 Happiness. Happiness is a hidden stat which runs from -100 to 100, and it is increased by caring and loving your Chao. Your Chao must have had over 30 happiness to reincarnate, so reaching this won't be hard.
- You must give your Chao all the animals native to the game in its current life. That means all 21 animals.
- Your Chao must be balanced, so that it would otherwise evolve into a Normal type. Your Chao must not be set to evolve into a Swim, Fly, Run, or Power type.
- The following requirements are different depending on which alignment you want your chao to be.
- For a Neutral Chaos Chao, or a Light Chao, your chao must have Neutral alignment.
- For a Hero Chaos Chao, or an Angel Chao, your Chao must be set to Hero alignment upon evolution.
- For a Dark Chaos Chao, or a Devil Chao, your Chao be set to be Dark alignment upon Evolution.