| Category | Depressions |
| Continent | Brucrumus |
| Region | Cinazan, Miradelgûn |
| Map | Drenvun Depression |
Drenvun is a submerged expanse situated in the eastern reaches of Brucrumus. Extending nearly 700 miles in length, it commences at the foundation of the Damreth Peaks. Progressing southward, it carves through the crimson glow of Âruk, then eastward where it discharges into Hullbreaker Bay.
Today, Drenvun is vastly different from its origins. In the creation of Bal-Kriav, the northern region of Drenvun extended the Damreth Peaks, then transitioned into Âruk's grasslands and wetlands. A Plaque of Alphar states that during the Creation War (1486 DE - 8777 DE), the land was warped by the presence of numerous dying primordials. Across a thousand-mile battlefront, stretching from the bay to the mountains, the land became contaminated with entropic energy.
The strategy was a novel one, a last-ditch effort. While small doses of their entropic release are managed organically, inundating it with the vitality of Chaos's deceased incites significant unnatural transformation. Highlands morphed into fields of debris, vast expanses of perpetual viscous mud, aromatic vents that will eventually breed discord, and worse, a submerged land, a fracture in what was once open terrain.
In solemn tribute to the fallen scout who perished in this locale, I humbly request that this region be designated as Drenvun.
Orallâchâr, captain within the 412th Covenant Recon - "Tale of Drenvun"
Since the Dawn Era, thousands of years later, the sunken land has transformed into a vast wetland depression. Lush pockets of dense foliage intertwine with bogs and serpentine rivulets. In certain regions, tangled swamps have formed, impenetrable to most. Countless ponds and murky pools dot the landscape.
The streams and rivulets descending from the Damreth highlands constitute the region's principal water sources. Progressing southward, these are supplemented by cascading waterfalls and subterranean streams gushing forth from cliff faces. Throughout the Ice Cap Melt period, Drevun experiences considerable inundation.
In the southernmost regions, floating settlements abound. Primarily situated upon shambog islands, these locales also feature numerous stilt-supported villages. These wetland-adapted communities serve as homes to humanoid inhabitants such as the Graagvrii, trolls, and the Bullywug.
Drenvun's northern regions feature sprawling subterranean tunnels that delve into the depths of Chaexidor. These tunnels interweave with the network leading to the kuo-toan dominion of Âkhi. Marauders from this empire frequently traverse these tunnels, emerging onto the surface to pillage food, treasures, and captives.