Hmm well let's see..
well, to quote the books:
" The Earth was destroyed.
Four worlds were created out of the ruin. Worlds for ourselves and the mensch: Air, Fire, Stone, Water.
Four Gates connect each world to the other: Arianus to Pryan to Abarrach to Chelestra.
A house of correction was built for our enemies: the Labyrinth.
The Labyrinth is connected to the other worlds through the Fifth Gate: the Nexus.
The Sixth Gate is the center, permitting entry: the Vortex.
And all was accomplished through the Seventh Gate.
The end was the beginning.
(in scrawled handwriting) The beginning was our end. "
So yeah, there were these two powerful races of wizards, the Patryns and the Sartan, who were fighting each other for generations, eventually the Sartan decided to tear apart the world into its four elements and throw the Patryns into a prison, where they will learn how to behave like proper civilized men. they had a wonderful plan to ensure each of the worlds will be a wonderful utopia where they could all rule over the "inferior" races, i.e dwarves, elves and humans, which are referred to as Mench.
...and of course every single plan they had goes terribly wrong, the labyrinth becomes a complete hell where everything is trying to kill you, the 4 elemental worlds which were supposed to support each other..well, didn't support each other, and the Patryns have escaped the Labyrinth, you could guess that they're feeling pretty angry and vindictive.