There are 11 regular races in DB:AO, and 3 ascended races. You can only have 1 character, therefore only being 1 race. You cannot swap races halfway through and keep your original stats. If you were to swap races you must start off with your new chosen race’s stats / items / location.
Each race has its own starting stats, items, locations and sometimes ships. They also have their own abilities (some are abilities that help out in battle, some that allow them to breathe in space or in water, useful for some planets, and some may gain more stats in battle etc).
Choose your race wisely ...
*** A Special Note on Ascended Races: Once you have become a Demi-God, God or DemonKing you cannot lose this status. Also, all ascended races get to make either a custom made move or transformation just 1x when they ascend into this state! ***