Allura's party traveled to investigate, but arrived to find this creature destroying everything surrounding the Gladepools, including Port Udall and Byroden. At the time, Lady Allura wasn't a part of the Council of Tal'Dorei she was a member of an adventuring party, much like Vox Machina.
Reports of a dragon-more massive than any on record-hit Tal'Dorei. He began razing the Mornset Countryside, south of the Verdant Expanse and the Stormcrest Mountains. After generations of secretly ruling the Island of Viscan, the dragon (now self-crowned as "the Cinder King") grew greedier than the island's limited resources could satisfy. Thordak became interested in Opash's notes and began to make his own additions to them, growing interested in the research into Guuthal the Ever-Fed, an ancient black dragon who evaded death by becoming a dracolich. These experiments made Thordak more powerful and eventually he destroyed the necromancer. Thordak had survived but was near dead from his fight with Devossa when he was captured by the necromancer Opash who experimented on him in his laboratory on the Island of Viscan in the south of the Lucidian Ocean. Rumors of a powerful drake storming the beaches and seas had been whispered for a long time while ships would be lost at sea. Thordak was not seen again for centuries, until about fifteen years before the events in " Desperate Measures" (1x40). He was presumed to have died shortly thereafter from his wounds. Eventually, he attacked Ank'Harel during its rise to prominence but Thordak was gravely wounded by the city's protector - Devossa - and retreated. Long ago, before maturing into an ancient dragon, Thordak lorded over half of the desert continent of Marquet for centuries. On closer inspection, Gilmore could see, instead of the uniform scales of a dragon, the heart crystal in his chest, smooth and jagged and pulsing with power. At that time, Thordak had the standard appearance of a red dragon, albeit an incredibly large and ancient one. Vox Machina first saw Thordak in the Elemental Plane of Fire.