Beneath the streets, plazas, and buildings of Raverie lies the Undercity — a vast, interconnected mechanical layer that spans the entire footprint of the city. It is not a separate settlement, nor a forgotten ruin, but an active, essential system that keeps Raverie functioning.
The Undercity houses the foundations of the city’s Modi: massive gears, transmission shafts, pressure corridors, sensor arrays, and maintenance networks. Every district above corresponds to a web of mechanisms below, forming a vertical city whose visible surface is only its calmest layer.
Narratively, the Undercity functions as Raverie’s diagnostic layer. Problems appear here first. Failures manifest here before they become visible above ground. It is the space where the city’s health is measured, not by people, but by motion, tension, heat, and rhythm.
The Undercity exists to serve three primary functions:
To house and connect the Modi that power, regulate, and synchronize the city
To provide controlled access for maintenance, calibration, and emergency intervention
To isolate failure, instability, and mechanical stress away from civilian life
It is not designed for habitation, exploration, or comfort. Every passage, chamber, and platform exists to support machinery first and people second — if at all.
For most citizens, the Undercity is an abstraction. They know it exists. They trust that it works. They rarely think about it unless something goes wrong.
The Undercity is not uniform. It is a layered network of spaces built over generations, expanded as new Modi were added and older systems adapted rather than removed.
Broadly, it can be understood as consisting of several overlapping types of zones:
These are vast subterranean spaces housing large-scale components of the Modi network. Rotational assemblies, synchronized gear rings, and load-bearing mechanisms dominate these areas. Many of these systems cannot be stopped without citywide consequences, making direct intervention rare and carefully planned.
Narrow tunnels, ladders, crawlspaces, and access shafts connect the larger chambers. These routes were designed primarily for elven technicians and specialized maintenance crews. Humans can enter some of them, but many are simply not built for human proportions.
Heat, pressure, and energy generated by the Modi are redirected through designated corridors and chambers. These areas are warmer, noisier, and less stable — conditions that have made them natural habitation zones for gremlins.
Distributed throughout the Undercity are monitoring systems that track vibration patterns, pressure thresholds, gear alignment, and mechanical rhythm. These arrays do not watch constantly in an active sense; instead, they detect deviation from expected behavior.
Older tunnels and chambers from early phases of the Modus Revolution still exist beneath the city. Some are partially integrated, others bypassed or sealed. These areas are less thoroughly mapped and less consistently monitored.
Together, these zones form a dense, three-dimensional network that extends beneath nearly every structure in Raverie.
Access to the Undercity is highly restricted.
The primary and most heavily regulated entrance lies within the Clockguard District, leading to the chambers surrounding the Modus Primus. From here, both humans and elves may enter under strict authorization.
Additional official access points exist near major institutes and maintenance facilities, though these are limited in size and function.
Throughout the city, smaller access points exist in the form of vents, maintenance hatches, and emergency shafts. Most are too narrow or inconvenient for routine use, especially by humans.
While humans are permitted in the Undercity under specific circumstances, it is not designed for them. Movement is slow, visibility limited, and many areas are physically inaccessible.
Elves, by contrast, are expected to operate here. Their size, precision, and training make them the primary responders and technicians below the surface.
The Undercity is not constantly observed by sentient oversight.
Instead, the city relies on a distributed sensor network that monitors mechanical performance. These systems track deviations — changes in vibration, pressure spikes, heat anomalies, or timing irregularities.
Only when a threshold is crossed does an alert propagate upward.
When this happens, signals are routed to the Clockguard, who deploy rapid-response teams — most often elven pilots and technicians — to investigate and contain the issue before it escalates.
This system allows Raverie to function efficiently, but it also creates blind spots. Sabotage, interference, or damage that remains within acceptable tolerances can go unnoticed for extended periods.
Elves do not control the Undercity. They manage risk within it.
Their presence consists of:
Defined patrol routes rather than full coverage
Rapid-response deployment rather than constant occupation
Focused protection of critical systems rather than territorial control
Certain areas are known to be unstable, low-priority, or too complex for routine monitoring. These zones are acknowledged but not actively patrolled unless conditions change.
This approach prioritizes efficiency over dominance and leaves much of the Undercity functionally unobserved.
The Undercity is the primary habitat of Raverie’s gremlin population.
Before the Modus Revolution, gremlins lived in basements, crawlspaces, and abandoned structures. As the city expanded downward, they migrated into the warmer, more dynamic spaces beneath the surface.
The gremlins understand the Undercity intuitively. They navigate by vibration, heat flow, and mechanical rhythm rather than maps. Their territories often overlap critical infrastructure, not by design, but by necessity.
Some gremlin groups attempt to sabotage the Modi, believing the city should be allowed to break or change naturally. Others simply survive within the system, scavenging and avoiding attention.
Despite frequent interference, the sensor network and elven response prevent most sabotage from escalating — though not all.
The faction known as the Grinding Gears operates primarily from the Undercity, using its complexity and partial invisibility as cover.
The vast majority of the Undercity is not accessible.
Most areas are:
Physically unreachable for humans
Too dangerous or unstable for routine traversal
Irrelevant unless a specific failure or threat occurs
The Undercity exists largely as:
An origin point for threats
A justification for rapid response and containment
A hidden source of conflict rather than a continuous setting
When characters enter the Undercity, it is almost always for a defined purpose: to investigate an alert, intercept gremlins, stabilize a failing system, or prevent a cascading breakdown.
Exploration for its own sake is neither common nor encouraged.