This world is but a dream, a figment of our imagination that is believed by one and all.  Where does this dream come from?  When did it start?  When will it end?  Well this dream begins with the dream of another, a creature much greater than most.  
A wurm made from the songs of the elements, and with but a whisper could make its dream a reality.  This wurm of silver and blue dreamed of a place with no pain, no fighting, and no hatred.  It dreamed of a place where creatures less than itself could have their own hopes and dreams.  
The wurm sang a song of fire, ice, lightning and stone.  With the singing came the lands and the seas.  The wurm sang a song of light, darkness, chaos and order.  With the singing came the laws that the world would come to live by.  The wurm sang of Life, Death, Reason and Dream.  With the singing came the thoughts, hopes, and energy for the world to use.
From this came Tyrra, her people, and all the creatures within.  The wurm was pleased, but found that the land was not as it had hoped.  The land still followed its dream, and not their own.  The wurm sang to the creatures, trying to convince them to follow their own dreams, yet only one heard its song.
A serpent of chaos, wriggling without a concern heard the call.  At first it didn't care for what it heard, but then it became angry at being controlled.  Why should it follow another's dream.  The creature came to the wurm, slithering through the darkness.
So caught up in its dream the wurm did not wake.  With anger the serpent tore the wurm appart piece by peace, and from its flesh came the kin.  The young ones, created from their mothers dying dream attacked the chaos and drove it deep into the world where they could not chase it any longer.  Without the dream of the wurm, the people of the plane had nothing to follow but themselves.  Thus was Tyrra created and named for the one who created it.  This is how we came to be, so we must continue the dream of life that has been granted to us.