A Pokemon is a non-human creature that is bred to do battle and be a faithful companion to humanity. However, there are no humans in Dimension Number 2. Any human that enters this dimension is transformed into a Pokemon instantly. The species depends on the personality of the human, their lifestyle, or a number of other factors.
Pokemon can do many things that humans can't: they can use moves and techniques in-battle and out; learn more powerful Advanced Moves as they gain experience; many of them can fly, swim, and even use psychic powers; only to name a few.
There are currently 493 known species of Pokemon, each with its own powers, skills, strengths, and weaknesses.
Each Pokemon can have up to two out of 17 possible types. Pokemon of a specific type are strong or weak against other specific types, and they usually learn attacks of that type.
In addition, each Pokemon has one passive ability that grants it an extra bonus.