Main Character and Storyline
There is a story of four Pokemon gods that were sealed in the legend balls. Missing for an eternity, the legend balls have been rediscovered in an area call Beaules. You control the main character and are able to choose your own name. Your character wants to become a Pokemon master like his older sister. Your rival is Eseal, who would become unstoppable with the power of the Pokemon gods. On your quest to become a master, you must also stop Eseal.
Supporting Characters
In the world of Pokemon Chaos Black, Professor Oak still sends you off on your quest to become a Pokemon master. He provides you with a starting Pokemon (you choose from three, as in other versions). The old man who first teaches you to capture Pokemon is exactly the same, as are the townspeople. They all say the same things as in Fire Red and Leaf Green. The first gym leader, Brock, is likewise unaltered.
Old Pokemon Characters
Many of the Pokemon encountered in Pokemon Chaos Black are the same as in Fire Red or Leaf Green. The old man who demonstrates catching a Pokemon uses a common Weedle. Random encounters will also bring you into battle with Ratatta, Onyx, Mankey and Spearow. All of these Pokemon are common to Fire Red and Leaf Green. Most of the characters you can battle along the way also use the same Pokemon as they do in the other versions.
Unique Pokemon Characters
There are new Pokemon in Pokemon Chaos Black that are not found in Fire Red, Leaf Green or any of the other Pokemon games. The starting three Pokemon are new. There are some interesting Pokemon, such as Shizard, Flaron, Tase, Magid, Abel, Glaag and Esplime. Visually, they are different from existing Pokemon, but their graphic quality is not very good. The elusive MewThree X looks like an alien version of Mewtwo, and appears as a level 100 Pokemon.