| Category | Ruins |
| Continent | Karterus |
| Region | Azrik |
| Built | 16 Dreamer 410 |
| Map | Vetoubahr |
Thegildreon is an ancient ruined stronghold in the Broken Lands. Built by this Melephaeusans, this edifice was a grandiose temple dedicated to the elven god Corellon. When the region was wracked by the Gulimbor Cataclysm (996 - 1203), a large group of Corellon devotees remained behind to protect the place. It was assumed they perished in the ensuing devastation, but a yuan-ti seer from Phlem claims something more sinister happened. His writings in the tome The Thegildreon Gateway claim that the Gulimbor Cataclysm opened a rift to an abyssal world under the heel of Demogorgon. On Bal-Kriav's side, this rift opened in the catacombs of Thegildreon. Secretly, succubi agents of this demon lord entered the complex, subverting some of the priests. What ensued thereafter was murder and the damning of the place as all manner of atrocities were carried out by elves and demons. The temple became a ruin, a nightmarish cursed place.
In 1130, the Irastâ tribe entered the ruin during one of the Broken Lands occasional magical storms. One tablet in the ruin, written before the Irastâ were turned into monstrosities, says the interior of the temple was in pristine condition, a welcome place compared to the wasteland surrounding them. A few years after the Irastâ's disappearance, Ba'lith's eastern frontier outpost came under attack by corrupted elderaunts speaking the demon's tongue Abyssal. They soon learned these marauders called themselves the Maleraunts.
In 1500s, Thegildreon was again used to corrupt those that stayed within its walls. These were slaves brought here from Smizerak. They returned home as half-demon dwarves.