Union
Unions are the five factions lead by the Five Foretellers. The Five Foretellers are Keyblade Masters, apprenticed to the same Master and each bestowed with a copy of the Book of Prophecy. Each Foreteller has an associated animal, and hides their identity behind a mask representing that animal.
Joining A Union
After the introductory cutscene and character creation, you'll be asked to join a union. Each union is similar to a game server in that you have no contact with anyone in the other unions. If you are planning on playing with friends, it is advised that you all join the same union.