The Player
During the process of creating your world in the World settings page you will be presented with the character customization screen.
This menu allows you change to look of the character for the world. Make sure you like how you look as you can only change your hairstyle and clothing later in the game!
Note: Characters are neither male or female but options are provided to give your character the appearance of gender by hair style and in game cosmetic items.
Characters can be used across multiple worlds and will also take across to a new world any items currently held in their inventories (Armor,Trinket slots etc also). This allows you to play a fully customized character in a new world or even assist friends/others in their own shared online worlds.