| Category | Marvels, Prisons |
| Location | varies |
| Owner | unknown |
| Built | 6 Hollow 8715 DE |
Near the culmination of the Creation War (1486 DE - 8777 DE), with triumph imminent, Coverant forces constructed the Thunder Halls as a penitentiary for perilous primordials commanding elemental mastery.
Thunder Halls is a large unanchored earth mote. It is a floating island of rock that traverses an erratic path across the middle regions of Brucrumus, extending from the High Wood Country in the west to Miradelgûn in the east. The mobility of Thunder Halls is attributed to a perpetual storm in its lower quarter, an enchantment bestowed upon the structure during the God Era. In the Demon Spawn War, Talos fought alongside the Quarat'un Covenant and, to prevent the prison from falling into demonic hands, he imbued it with a perpetual storm, ensuring its constant movement.
The most prominent features on the surface of Thunder Halls are its four colossal towers. Each is composed of the fundamental elements: fire, water, earth, and air. At the center of these four towers stands a prismatic glass keep. Those who have ventured to this place claim the keep's prismatic glass possesses all the properties of the Prismatic Sphere spell. The pinnacle of rock forming the base of this keep and its adjoining towers has been melded into a single, massive block. The creation of this structure was carried out by a team of fire elementals, who battered it into shape using their maul-like fists, followed by a group of colossal earth elementals. Finally, the work was cooled by huge water elementals and meticulously sculpted by a team of air elemental artists.
In the Second Epoch, the arch-mage Nevicanad was entrusted with a key to this ancient Coverant prison. A consummate conjurer, he expanded his arcane knowledge through dialogues with the prison's four elemental princes. Drawing upon the ancient wisdom of these elementals, along with a measure of their essence, Nevicanad crafted two potent magical items. The staff Darkwind was forged in the Whirlwind Tower, while the halberd Embercackle was created in the Furnace Tower. In the Earthen Tower, Nevicanad discovered the great hammer Mudmaul. However, Nevicanad never completed a fourth item, one intended to harness the power of water. It is said that during the creation of this unfinished item, the elemental princess Olhydra broke free, capturing the arch-mage.
In 1823, daring adventurers infiltrated the Thunder Halls. As a reward for the treasures they seized, they liberated three Elemental Princes, who promptly departed and returned to their Elemental Ring Worlds.
When the Elemental Princes were imprisoned in Thunder Halls, they were bound in their antitheses. The Furnace Tower held Olhydra, the Waterspout Tower secured Imrik, the Whirlwind Tower imprisoned Ogremoch within a perpetually raging tempest, and the Earthen Tower entombed Yan-C-Bin.
| Name | Released | Other |
|---|---|---|
| Imix | 1832 | Prince of Evil Fire Creatures |
| Ogremoch | 1832 | Prince of Evil Earth Creatures |
| Olhydra | 1796 | Princess of Evil Water Creatures |
| Yan-C-Bin | 1832 | Prince of Evil Aerial Creatures |
| Typhalumus | 8992 GE | elder water elemental, Typhalumus volcano |