Lore: The Thulgrähbar and the Undersea
The Thulgrähbar are dwarves who live far beneath the surface-world, dwelling upon islands in the Undersea. Descendants of Clan Steelbright, millennia ago they delved back into the Deepings from which the dwarves had first emerged, and they remained there. Thindul's depth's were not yet flooded then, and for many lifetimes they mined, and carved, and smithed beneath miles of stone, until the War of Broken Thoughts.
In the year 2795, Pre-Sylvan Reckoning, the servants of Nerophet descended in discs of steel from their citadel within the moon. The great urnäkki, Ansadyr, and its numberless progeny swept over the world. They were repelled at great cost by an alliance of mortal peoples, with elves and dragons counted as Thindul's finest champions in the war. At last, the warrior god Qoth drove Ansadyr from the moon in single combat, taking the sky citadel for his own. The urnäkki fled with its children into the Deepings and settled there.
In the years that followed, the corrupting presence of Nerophet's servants began to permeate the world beneath. By day, the Thulgrähbar were mired in paranoia and despair. By night, they dreamed the dream of Nerophet's peace. And the Man with Long Teeth came into their thoughts, promising them respite. As with all who peer into the mind of the Abyss, little by little the Thulgrähbar came to realize that the silence of Nerophet must be spread across Thindul. For in any corner of the cosmos where there is sound, or light, or movement, these things offend the tranquility of His contemplation. All things are suffering.
So the Thulgrähbar made war on their kin, the Ironheart and Steelbright clans, seeking to bring them under the sway of their new god, or else exterminate them. For thousands of years, the dwarves of the mountains recused themselves from the world above, to fight their corrupted subterranean brethren. For ages they held, helped often by the gnomes of Nidulandar and its vassals. Then, around the year 600 by Sylvan Reckoning, the Thulgrähbar began to tunnel toward the sea. They built vast sluice gates, and in the year 822 the Thulgrähbar flung them open, flooding the Deepings.
Thus, Nerophet, the Shadow in the Sea, came to dwell beneath the stone of Thindul. In the deluge, the delvings of dwarven and gnomish kind were flooded. Of their hundreds of cities beneath the earth, only a scattered few remained. The Thulgrähbar were no less devastated, and they rejoiced. Nerophet swallowed many souls that day. As this cataclysm played out below Thindul, grasping tides spread over the shores of the world above, and horrors rose from the sea's deep, carrying down untold victims. Later, these dark days were known to mortals as The Silent Tide.
More than a century later, the year 985, Brecca Ironheart led a great delving of many thousand dwarven heroes, and countless more mercenaries, back to the Undersea. After a year of brutal war through winding caverns, and over black and sunless waters, she seized the sluice gates from her Thulgrähbar foes, and drove them far into the dark recesses beneath Thindul. The Ironhearts debate now whether to fully close the Thulgrähbar sluice gates, or to preserve the Deepings as they are. For in the century that has passed since the Silent Tide, dwarven and gnomish civilization have come to depend on the sea beneath the world, every bit as much as they revile it.