Tymarell was once a wealth city located in what is now modern day Rakore, just north of the town of Takanal. The city was benevolently ruled over by the silver dragon Killishandrastatia, who left the day-to-day running of the mining city to the dwarves and humans that she befriended. Silver, mithril, and precious gems flowed from the mines of Tymarell during its glory days, sometime around 200-300 Avard. The city was destroyed by a pyroclastic flow in 305 Avard.
The silver dragon Killishandrastatia was killed in the flow, as was most of the human population of the city. The dwarves, however, were spared – in a way. They were trapped beneath the pyroclastic flow, and many of their elders were lost. The remaining dwarves remained in place, digging deeper within the mountain, using its geological heat to power a city they named Daggoneth.
All that remains of Tymarell are its sewers, the upper portion of the city having been buried by the flow.
The troll known as Grythe has made his lair in the former sewers, and the dwarves have been content to leave him there. Grythe has learned to leave the dwarves alone, and he serves as an effective guard against any who would seek to plunder Tymarell or invade Daggoneth.