Zax is the location where the player first spawns at in Ultimate Lego Universe.
Zax is an icy planet, far away from the main system in ULU. Because of this, Lord Hixel has sent his scouts there to protect it (weird, right?) As it turns out, deep inside Zax is tons of crystal, the source of Hixel's powers. The player spawns there and recieves word from Mark, second in command of the rebellion, asking for he/she to train with him to help improve their skills. The player agrees, and is comfronted by Rouge Soldiera. Mark sends over a a level one plasma gun to help the player. Later in the game, the rebellion asks the player to return back to Zax and destroy it and its crystals. Afterwards, Hixel searches the galaxy for more crystal.