Add a new Dynastic Rule to the Ruleset.  Call it “Races” and give it the following text:

Each Adventurer has a creature type (abbreviated ‘Race’)  tracked in the GNDT under a column called “Race”.  A race may be any word between three and twelve letters long, but Adventurers are encouraged to be a Race from the set {Elf, Fairy, Gnome, Dwarf}.  An entity (including an Adventurer) who has a Race and whose Race is not Elf, Fairy, Gnome or Dwarf is called a Monster. 

New Adventurers start with a race of “Baby”.  An adventurer with a Race of “Baby” may set their Race to Elf, Fairy, Gnome, Dwarf or Ogre at any time.