The army of Naz Gorfuung, the northern dominion of drow, goblins, orcs, and kobolds, had laid siege upon the underground dwarven city of Calegrim in the kingdom of Isdagor. Around the city were many catapults and trebuchets, and the walls of Calegrim were bombarded with heavy boulders day and night. After three days of constant bombardment, the walls of the city shattered. Indeed, not only did the walls shatter, but much of the walls of the cave of Isdagor itself crumbled, and behind this wall was an ancient and long-forgotten tunnel.
The invaders did not see this, and they stormed the city, putting hundreds to the sword. Not long did they revel in their victory, however, for out of the ancient tunnel they had unearthed came tens of thousands of wights, skeletons, ghosts, wraiths, and all manner of undead. This army of undead swiftly defeated so many of the invaders that there were no living races that remained in the city.
After they had went through the city, the undead masses dispersed throughout the caves and halls of Isdagor. Even as they dispersed, more flooded through the tunnel, for that tunnel was the Underworld's Gate, an ancient portal to the Underworld, which had long since been sealed and forgotten.
The Underworld is the ancient cesspit of death and all things vile, and its ruler was the most vile and wretched of them all. The Black Flame, who was Gulgoth in life but had abandoned that name before men had walked the earth, was the leader of the so-called Black Horde, or Rath Gulgoth to the elves.
Soon, the undead spilled out of Isdagor, and destroyed everything in their path. In five days, the dwarves were completely driven out of their home, indeed there were no living races remaining in all of Isdagor.
The southern alliance of Caer Thulmin, the alliance of humans, elves, dwarves, and halflings, soon knew of this threat, and met those of the Black Horde that had came out of Isdagor's southern gate with the full military might of Caer Thulmin. Their battle raged for many hours, and Caer Thulmin managed to push the undead back into the caves.
A similar fate became of the Black Horde who had poured out of the northern gate of Isdagor, where they were met by armies of orcs, drow, goblins, and kobolds. The battles that day were legendary, and the undead on both sides were driven back into the mountains. But this was only temporary, as the Black Horde regained their strength.
Not only does the Black Horde threaten the races of halflings, drow, dwarves, elves, goblins, humans, orcs, and kobolds, but these same races are divided against each other, and they even now march into war. Many citizens have taken up arms against either faction or the Black Horde itself, in hopes of honor, fortune, or simply an eventual peace. Still many remain that care little about the war, and prefer their simple, honest living to the constant danger of battle and war. It is the year 552 of the Fifth Age, and the great continent of Tyradia is one of opportunity, both in arms and by trade.