In [Arventad], things are different. With the murder of the ur-god at the hands of a wayward human three centuries ago, the balances began to change. The protective angels of the ur-god's armies were left without leadership, support, or the motivation for good. Capitalizing on their latent power, they turned malicious and cruel, staving off their boredom by deceiving, torturing, and slaughtering those they once warded from harm. There are still a few pure angels among the clouds, but having found the populace's trust extremely hard to gain, they remain in reluctant exile.
All angels still carry their inborn fear and hatred of demons and their devilspawn however, and with this unexpected turn of events, the demons of the Helfields, who were expected to rise up from the ashes of the ur-god's defeat, were instead forced to defend both themselves and their once plentiful source of souls from the onslaught of the angels. Abandoning their old ways of unchecked sin and crooked contracts with the lesser races of [Arventad], the demons began forming truly protective pacts with them. The humans were reluctant at first, but the assailment of the angels was enough to drive a man to do anything, and the demons eventually became the selfish guardians of humanity--a humanity that was consequentially becoming a twisted mockery of itself.
Abandoned and hunted by the angels they once worshipped, and left to bargain for assistance from the demons they feared and were taught to avoid at all costs, human society was crumbling. Forced to sell their souls for the selfish protection of the demons from the murderous cruelty of their own gods, humanity was reduced to small collections of amoral, paranoid scavengers. With their precious numbers dwindling, and the demons doing everything in their power to keep the stillsouled safe, the once feared and ostracized necromancers became a necessary evil to fill the need for farmhands, their undead abominations tilling the earth to sustain the yet living.
The consequences were not quite as tragic for the other lesser races though. With the humans preoccupied with their own survival to wage prejudiced, oppressive wars, and both the angels and demons turning a blind eye to what they too believed to be savage, honorless animals, the orcs and goblins were allowed to advance. In an almost complete reversal of the humans, the proud orcs formed a noble society of lords and knights. Likewise, it was soon discovered that the minds of the weak goblins, who had at that point in [Arventad]'s history been used mostly as frontline fodder for the orcs, could be molded in positive ways as well as negative, and they found their place in the new orc society as scholars and thinkers.
With the absence of the ur-god, the balance of nature also shifted. The green things of the world had slowly begun to wither. The elves were the first to notice the change, and they tried frantically to nourish the land. After their valiant efforts failed to provide any results, the proud elves declared it to be a sign of irreparable doom and exiled themselves from their slowly dying forests to the dark underground to wallow in their sorrow for the world.
Inversely, the dwarves felt the shift in nature and, adhering to their need for balance and stability, they turned their attention away from their greed for metals and gems. Adopting druidic lifestyles, the dwarves left their underground halls, leaving them vacant for the self-exiled elves to take up residency in, and migrated to the shriveled forests of the surface, hoping to understand and restore the unbalance left in the ur-god's dearth.
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That's what I've got so far. If you don't see the gimmick, [Arvented] (placeholder name) was your basic fantasy world until some kid from a farm goes on an epic adventure that leads to the death of the ur-god to "free" the world, after which all the races of the world switch roles with their "counterparts."
I'm going to use the world mostly for role-playing and short stories, but I want it to have it make as much sense as possible, and maybe make it seem a little less forced.
Any help is greatly appreciated. The elves and dwarves need the most work of what I have.