Legend has it...
Before the creation of the universe, five Elemental Creatures lived in the peaceful bliss of a Heavenly paradise.
In a series of unknown events...
The Light Demon seemed to have disappeared at an unknown cause, the Light Element seemed to not get passed on.
As for the Fire Demon, he has passed the Torch on to a young human male, the Torch began to be passed down for generations.
The Earth Demon has went to live on, but hides within the Human World.
The Air Demon has went on to live forever and never created a torch to pass on the Air Element.
The Water Demon has never brought apon the Torch either, and as well went to live forever.
As for the Shadow Demon, he decided to create a Legacy to pass down his Element from Guardian to Guardian.