New World Order
It has been millennia since the arcane energies of the Metamorphosis calmed, and nearly twice as long since it began. The Metamorphosis changed the world; what was once a temperate world with varying regions of grass, forest, ice, and sand now is comprised of those elements interlaced with arcane magic.
Whatever deities once controlled the surrounding planes vanished with their followers, and their domains now lay dormant or overrun with those who forced their way into the abandoned planes. New deities have emerged and are revered in the place of old, any remnants of the old gods are seen as primitive or seen purely as historical relics with no meaning today.
Though historians have tried to uncover the cause of the Metamorphosis, the only things they know about it since it has settled is that it started with a big bang of arcane energies. The most common theory is a powerful wizard, or perhaps a group of them, tried casting a spell to reform the world and it went awry, spiraling out of their controlled and leaving chaos in the spell's wake.
It is believed that almost every living creature died when the Metamorphosis began, though evidence today shows a variety of living beings, meaning that somehow life held on during the torrents of twisting magic. In it's weakened state, the world gave way to portals to other planes during the Metamorphosis, and now it is not uncommon for demons and devils to roam the world. They for the most part stay away from fortified cities, but villages deal with the stray demon here and there.
You've all been trained in your arts and now the local nobility has enlisted your aid in their personal guard. The promise of gold allures some of you, while the idea of doing good deeds drew in others, and even then some of you may have had other reasons. And now, you are almost at the gates to your new headquarters.