Dungeon

The Dungeon

The Dungeon (also called the Underworld or the Labyrinth) is a vast, planet-wide network of tunnels and chambers that exists beneath the surface of Ersetu. It connects to the surface world through openings both large and small, and descends into depths that no human has ever fully charted. It is the source of all ambient mana in the world — and the deadliest environment known to civilization.

The Dungeon and Mana

The Dungeon is extraordinarily rich in ambient mana, and the deeper one descends, the higher the concentration becomes. This effect appears to never stop — it is rumored that past a certain depth, the ambient mana becomes high enough to passively induce Mana Poisoning in unprotected humans.

Mana flows upward from some unreachable place far underground, thinning as it is absorbed by tunnel walls and the life forms inhabiting them. This flow is usually accompanied by air currents that keep dungeon air breathable. Where the Dungeon connects to the surface, the escaping mana creates Mana Wells — and it is widely believed by mages that all ambient mana ultimately originates from the Dungeon.

Ecology and Layers

All dungeon creatures are magical in some way, relying on the high ambient mana to survive. The deeper one goes, the more powerful and alien the creatures become:

Layer Creatures Danger Level Human Presence
Surface (Shallow) Magical variants of mundane animals (fire beetles, agile bats). Aranea webs. Moderate Extensive — pacified and commercially exploited
Middle Increasingly alien, unrecognizable species. Sapient but territorial. High Minimal — even experienced mages die here
Deep Utterly alien entities (exist in two places at once, possess pocket dimensions) Lethal None — even archmages wouldn't last long

The shallow layers are routinely pacified to serve as storage, experimental chambers, and mining areas. Several sapient races make their home here, maintaining complex but surprisingly peaceful trade relationships with humans.

Origins and Theories

The Dungeon's existence is a mystery. There are competing theories:

Regarding creature origins:

Economy and Travel

The Dungeon is vital for the modern economy — it is the only source of Crystalized Mana, which powers trains, industrial machinery, and complex spell matrices. See: The Dungeon Delving Industry.

While it is theoretically possible to travel through the Dungeon to bypass surface obstacles, it is extremely dangerous. Surface sections are poorly connected, forcing travelers into the lethal Middle Layer. Progress is slow, ambushes are frequent, and dungeon creature flesh is highly magical and toxic to humans, requiring travelers to bring their own food. No one has ever successfully crossed an ocean through the Dungeon.