Armok sat in his hall, gazing down upon the world. He saw that the flow of glorious blood had begun to slow. The humans had made peace with the elves, and the goblins were all but wiped out. Even the dwarves were content and secure in their halls. "I need a new race," he thought to himself. "A race to continue the slaughter. Or maybe not a new one. Just an old one... but modified."
Armok smiled.
The fire imp awoke. He didn't really wake up, but he definitely felt different. He felt... sentient, like he hadn't really had such thoughts before. He felt naked and confused, and mostly he just wondered if anyone else felt like this. He swam through the magma over to another imp, staring blankly off into space. As the first imp touched the second, a light came into the second imp's eyes. "Hey, what's happening?" she said. "I don't know," he replied. "Let's go wake up everyone else, shall we?"
As the two imps swam, spreading their newfound sentience, the imps began to swim to the surface and gather together. Eventually they reached the surface in huge hordes. As they interacted with the old civilizations, they gained knowledge. From the dwarves, with whom they felt a special kinship, they learned the secrets of steel and stonecutting. From the humans, who they were in awe of for their massive size, they learned the art of building and language. From the kobolds they learned to sneak and fight. And from the elves, well... they learned that fire imps and elves mix like oil and fire.
The imps eventually organized themselves into one huge civilization. They built themselves a city, and set the first imp, who had taken the name Flame, over themselves as king. They believed themselves over all other races, and expanded their empire. After all, they were chosen by Armok to make the blood flow. They ate enemy and livestock alike, and took slaves of their conquered peoples.
Some time after the emergence of the imps, the druids of the five elven civilizations met under a tree so old that it had witnessed the world's birth. The druid who had called the meeting, a soot-stained young elf wearing singed clothing, spoke of the death of his master, the burning of his forest, and the near collapse of his nation. The other druids sympathized. They had all lost friends to the joint armies of dwarves and imps. But the near collapse of a civilization? Something had to be done.
The elves contacted their gods. Several offered to lend their strength to an elven soldier in combat, or blight the enemies, or some other action pertaining to their sphere of influence. One god spoke against this, however.
Yonali Smithwings, who had become a god upon her death, had another idea. The elves needed to gain more allies not more power. She suggested teaching the animal men that filled their lands the ways of civilization. The druids agreed, along with most of the gods, who admired Yonali for what she had done for elvenkind in her time. The elven animal trainers captured as many animal people as they could and began to teach.
The next summer saw a massive army of elves, animal men, and war beasts sweep down out of the forests to retake what had previously been elven lands, but now belonged to the imps. The fire imps, initially taken by surprise, counterattacked with an army of their own. The dwarves soon joined the battle as well, and the fighting claimed thousands. The dwarves and imps were pushed back by sheer numbers, and they each made a fighting retreat to their fortifications. To say they were surprised would be an understatement when they found themselves ambushed by a second army just as large from behind. The dwarven and impish armies dug in, just trying to stay alive while waiting for reinforcements that would never come.
Armok, seeing all this, foresaw what would happen if he let things continue happening as they were. He would not let such brave warriors die of starvation, far from home and hearth. He saw a way to both save the dwarves and keep the blood flowing, and with only a minimum expenditure of power.
So he took away the animal men's ability to speak.
Without the ability to talk to each other, the joint army soon disbanded out of mutual frustration. The dwarves and imps took their wounded and went home. The animal men, in the meantime, were busy founding capitals, choosing governments, and electing leaders. They did not all join together, preferring to stick with their species, but they all had roughly the same ideas on government. Soon the animal men's forest retreats, (or menageries, as the dwarves called them), spread throughout what lands had not already been claimed. They even clashed with the elves, seemingly forgetting who had given them the taste of civilization in the first place. Eventually they settled down once they were content with what they possessed.
The goblins were facing extinction. The dwarves, human, and elves were bad enough to begin with. But then the fire imps came, and now animal men? There were only a few dark fortresses left! The goblins were willing to turn anywhere for help. The goblin's legends spoke of demons from the underworld that had led their species to great victories in the past. The goblins decided to let out a demon from the underworld. They broke into an adamantine spire and set loose a single demon, then closed the hole with an obsidian patch. The demon became the master of the goblins, but he was not quite happy yet. One night, he stole a pick and went down to the adamantine. With one massive swing he bashed the pipe wide open. His demon brethren poured out with him at their head. They flooded up through the caverns and onto the surface, not harming a single being. Common courtesy exists even among the demons.
They poured out and founded towns from which to raid. The demons swept across the land, living only to consume and destroy. Nations fell beneath their invincible might. Sworn enemies banded together to drive back the demons. It was a dark time for civilization. But the blood flowed.