There are four common races that are known throughout Earth:

MUTANTS: Better  known as "Mutoids", these odd-looking humanoids evolved  from
nocturnal hunters who were exposed to harsh radiation from the last World War.
Mutoids have snouts similar to those of wolves and have flaps of skin  between
their sides and arms like flying squirrels.

CYBORGS: At one time there was a highly-advanced technological human race that
was on  the edge of  extinction  due to post-nuclear  radiation.  Fearing that
their kind would be wiped out, they devised a  way to combine their technology
with human  genetics.  The  result was a  type of living-thinking  robot.  The
civilization  programed  all of  their knowledge and  intelligence into  these
creations  and therefore saved their race  from  dying out.  Cyborgs  are half
man and half machine.

HUMANS: Until the World War, the Human race populated the planet in very large
numbers.  The Humans  were the  inventors of the  atomic bomb, which, in turn,
destroyed nearly their entire planet.  The  beliefs for Humans now  is just to
merely survive and seek revenge on their dreaded enemies.

ALIENS: This  race immigrates from another  galaxy to Earth in search of trade
and water crystals.  Aliens hardly mix  with Humans that often.  They consider
themselves more intelligent than other races and  boast their egos by speaking
of their home planets. They are also very philosophical and are well known for
their unusual ideas.