The Tectonic Cults

From its beginnings as a miners’ warning circle, the movement grew by offering route knowledge, shelter, and purpose to people neglected by more powerful interests. The collapse at the old stone barrier changed its direction: believers saw a reply from the deep, while skeptics saw a preventable disaster. The resulting split gave the movement its enduring contradiction. It still preserves valuable safety knowledge, yet it increasingly uses that knowledge to choose where and how to cause damage. The Cult established influence around the Obsidian Vaults by controlling access to vents, passages, and old workings. Its members became sought-after guides before they became feared saboteurs. As its doctrine hardened, the Cult began to treat the ancient containment systems as instruments of oppression. Its raids for relics and seismic mana-crystals have brought it into open conflict with Ward-Master Korath and with settlements that depend on stable air and water. Today its reach is strongest near the Vaults and along major fault lines, but its cells are divided over the scale of the awakening they seek.

Faction

The Tectonic Cults

To some deep communities, the Cults are dangerous saboteurs who may poison the very tunnels everyone shares.

Type: Fanatical religious…
Size: 75 members
Reach: Locally dominant around…
Base: Obsidian Vaults

Overview

How it began

The Tectonic Cults began as a small circle of Oread miners and route-keepers who met after Kaelen’s discovery of troubling signs in the deep stone. At first they mapped unstable passages, recorded strange tremors, and warned communities away from unsafe workings. Their earliest gatherings were practical affairs: chalked routes, shared water, and arguments over which tunnels could still be trusted. Their turning point came when a mining operation broke through an old stone barrier and caused a collapse. Survivors claimed they heard Terravorus answer from beyond the broken rock. Kaelen came to believe the tremor was proof that the surface was drawing too heavily on a sleeping power. The circle divided. Some wanted to seal the breach and keep the warnings quiet; others saw the collapse as a sacred summons. The latter formed the first Seismic Heralds and began recruiting among displaced miners, pariah communities, and those who had lost kin to hazardous excavations. Over time, protective route-work became a doctrine of liberation. The Cults began to treat ancient seals as shackles, and sabotage as a necessary warning to surface interests. Their largest triumph was securing a network of passages around the Obsidian Vaults. Their gravest setback was a premature breach that filled an inhabited gallery with sulfurous fumes. The disaster was officially blamed on a failed excavation. Inside the Cult, it became the defining argument between those who would open the deep at any cost and those who fear the thing their faith may awaken.

How to know them

MottoThe surface is a crust of lies; true strength sleeps in the dark magma below. Crack the seal, free the core.

EmblemA black split-stone disk crossed by a red fissure, with three short strokes beneath it. The strokes represent the numbered fault branches on a damaged survey plate once used by deep route-keepers.

Colours

Basalt black, Sulfur yellow, Furnace red

Signs

A split black-stone disk marked with a red fissure
Three strokes copied from an old fault survey
A heated iron ring worn by some members as a sign of service at a vent shrine

DressThere is no universal uniform. Seismic Heralds tend to wear layered, heat-darkened robes and carry stone-listening instruments. Slag-Borne Zealots use heavy basalt armor that muffles movement but limits agility. Fault-Breakers favor practical mining clothes, reinforced gloves, and detachable insignia so they can pass among workers.

Standing

AlignmentFanatical and destructive, though many members see themselves as protectors of deep communities rather than villains.

AgeThe network took recognizable form roughly forty years ago, after miners and route-keepers began gathering around reports of unusual tremors beneath the Under-Roots. Its exact founding date is disputed.

WealthModest in coin, comparatively rich in route knowledge, rare mineral stores, access to hidden workings, and leverage over dangerous passages.

What they say they want

Protect the Under-Roots from reckless excavation.

Keep dangerous passages and unstable vents from being exploited by outsiders.

Secure the deep communities’ right to decide what may be mined, mapped, or sealed.

Preserve route knowledge and warn residents of approaching geological hazards.

What they are doing now

Find and breach the primordial vaults beneath the Obsidian Vaults.

Acquire the seal-key held by Ward-Master Korath, though not all Cult cells agree on whether it should be stolen or copied.

Harvest raw seismic mana-crystals from active fault lines.

Disrupt air-scrubber and sluice systems in settlements that obstruct access to the deep rifts.

Recruit the aggrieved and the displaced by presenting the Cults as defenders of the Under-Roots.

Where it leads

The Cult imagines a world in which the deep earth is no longer mined, mapped, or sealed by surface powers. It wants the Under-Roots’ routes and resources governed by those who live below, with primordial forces released as guardians or instruments of a new order. Whether such a world could exist without catastrophic devastation is the question the Cult refuses to answer.

How others see them

To some deep communities, the Cults are dangerous saboteurs who may poison the very tunnels everyone shares. To others, they are the only people willing to resist those who treat the Under-Roots as a resource to be taken. Their scouts are known for accurate warnings; their raiders are feared for making those warnings come true.

People

5 ranks

High Speaker and Core-Herald

High Speaker Malakor Earth-Eater

Quiet, persuasive, and intensely certain. Malakor offers food and shelter before asking for loyalty. He can show genuine tenderness to the dispossessed, yet accepts mass danger as a price worth paying for what he calls liberation.

High Speaker1 member
Malakor Earth-Eater directs doctrine, assigns major operations, and claims final authority over when a seal may be approached.
Seismic Heralds5 members
Priests, occult specialists, and interpreters of tremors who map fault lines, locate gates, conduct rites, and advise the High Speaker. Their order is named for the five marked stations on an obsolete survey plate.
Slag-Borne Zealots18 members
Basalt-armored shock troops recruited from radicalized Oreads, Drow pariahs, and Dao mercenaries. They protect shrines, escort expeditions, and hold captured passages.
Fault-Breakers11 members
Infiltrators and saboteurs who use charges, resonant wedges, and local knowledge to obstruct tunnels or damage air and water infrastructure. Their title derives from an old military map marking a breach as Fault-Breaker 2.
Cinder-Votaries40 members
Initiates, scouts, supply handlers, and sympathetic residents who carry messages, gather rumors, and maintain the Cult’s scattered shrines. The name is a worn corruption of a miners’ term for those assigned to tend vent fires.

Other key members

Ward-Master Korath Keeper of the seal-key and principal local opponent
Sethri Route guide and uncertain ally
Ktagh of Station 4 Fault-Breaker organizer

How they are organised

How it is runA distributed religious network with a central speaker, shrine-based specialists, militant crews, and loosely affiliated local cells

Who comes nextThe High Speaker’s successor is chosen by a conclave of active Seismic Heralds, who must agree that the candidate can interpret the deep and command the cells. In practice, control of the seal records, shrine network, and Slag-Borne Zealots weighs as heavily as doctrine. Malakor has not named a successor, and the Heralds disagree about whether the next leader should be a radical Unsealer or a cautious Measurer.

How they recruitRecruitment begins with practical help: a warning about a dangerous passage, a shared meal, or shelter after an evacuation. Interested people are invited to learn the Cult’s route signs and assist a local cell. Full initiation involves a descent to a fault shrine and an oath to protect the deep from exploitation. The rites vary between cells, and not every initiate is told that the Cult intends to break the seals.

To join

Accept that the surface’s claims to the deep are not automatically legitimate.
Swear to protect the Cult’s routes, shrines, and members from hostile intrusion.
Complete a supervised descent to a fault shrine or undertake a meaningful act of service for a deep community.
Do not enter a sealed vault or take a relic without authorization from a Herald.

Operations

What they do

Recruiting among people harmed or displaced by deep excavations

Mapping unstable passages, vents, and fault lines

Guarding shrines and controlling access to deep rifts

Sabotaging air, water, and trade infrastructure

Stealing seal-keys, excavation records, and seismic mana-crystals

Conducting rites intended to breach ancient primordial containment systems

How they do it

Recruit among miners, outcasts, and families displaced by dangerous or extractive workings.

Use route-keepers and sympathetic residents to monitor expeditions and settlement infrastructure.

Map tremors through listening rites, instrumented stone, and eyewitness reports.

Sabotage tunnels, scrubbers, and sluices to delay access or punish perceived exploitation.

Acquire seal-keys, excavation records, and mana-crystals through theft, bargaining, or armed raids.

Stage public rites that frame natural tremors as proof that the deep is alive and under assault.

Services for hire

Fault-line escortNegotiated favor, shared intelligence, or a substantial trade payment
A guide familiar with selected routes through Sub-Levels 2–4. The Cult will not guarantee that every passage remains safe.
Tremor readingA service owed to a local cell, or payment in tools, food, or reagents
Access to a shrine where a Herald can compare a party’s observations with the Cult’s records of local tremors.
Deep-forged suppliesTrade or a favor, with prices changing according to trust
Elemental gem reagents and heat-resistant equipment gathered or acquired by the Cult. Quality and safety vary by source.

What they can do

Strong local knowledge of selected routes, vents, and fault lines

Ability to detect some tremors and geological changes through trained observation and custom ritual instruments

Access to basalt armor and specialized tools for working near intense heat

A network of concealed shrines and temporary shelters

Some Heralds use custom elemental rites. These are setting-specific abilities, not claims about standard class or spell features.

Senior members can arrange dangerous passages through Sub-Levels 2–4, but such routes may be unstable or politically contested.

What they have

Concealed routes through portions of Under-Roots Sub-Levels 2–4

Shrines positioned near volcanic vents and known fault lines

A limited stock of raw seismic mana-crystals

Basalt armor, mining tools, resonant wedges, and localized charges

Informants among miners, scavengers, and displaced residents

Fragments of old survey records and reports of ancient containment structures

Where they are weak

The network relies on secrecy and local knowledge; losing trusted guides can make its routes dangerous even to its own members.

Its cells are divided on doctrine, tactics, and the acceptable cost of awakening a primordial power.

Sabotage of shared air and water systems undermines the Cult’s stated claim to protect deep communities.

The Cult has no reliable proof that the entity it seeks to awaken will obey, understand, or even recognize its followers.

Its basalt armor, crystals, and ritual sites are difficult to replace.

Malakor’s authority depends on his image as the one person able to interpret the deep. Evidence that challenges the founding story could fracture his following.

Territory

Headquarters

Obsidian Vaults

KindFortified shrine and concealed network of chambers within a ruin-side excavation settlement

The Cults’ central refuge occupies chambers and old excavation galleries within the Obsidian Vaults, a settlement of roughly 340 residents in the Abyssal Fractures. Their most sacred meeting place is called the Hearth of the Shattered Core, a name translated from an older miners’ phrase whose original meaning has been lost. It is a cavern warmed by volcanic vents, its basalt floor scored with fault maps and its walls stained orange by mineral vapor. The Cult keeps its relics behind guarded stone screens, while its outer galleries conceal routes used by pilgrims, smugglers, and raiding parties. The settlement is not wholly theirs: residents, wardens, and other workers continue to live and trade in the same precarious enclave.

Lands they hold

The chambers and routes surrounding the Obsidian Vaults

Select passages in the Under-Roots’ Sub-Levels 2–4

Fault shrines and volcanic vents where the Cult has established watchers

Concealed routes near the deep seals, whose locations are guarded closely

Outposts

Vent Marker 2Under-Roots Sub-Level 2, near an active volcanic ventA listening shrine used to interpret tremors and shelter scouts during periods of dangerous gas flow. Its name comes from the number on an old vent survey.
The Sundered HearthUnder-Roots Sub-Level 3, beside a collapsed routeA recruitment and supply chamber named by corruption of an older miners’ phrase for a warm refuge beside broken stone.
Fault Station 7Under-Roots Sub-Level 4, near a sealed fault gateA concealed watch post where the Cult records movement around the lower seals. The designation survives from an obsolete military map.

Secrets

The big secret · GM only

The collapse that transformed the original route-keepers into a militant movement may not have been a spontaneous answer from Terravorus. One surviving account suggests the mining operation broke the stone barrier only after someone weakened it from within. Malakor has seen a version of this account and suppresses it because it could mean the Cult’s founding revelation was engineered by one of its own early members.

What they really want · GM only

Break at least one primordial seal and use the resulting event to force surface settlements to abandon contested deep workings.

Secure Malakor’s authority over any first contact with the power beyond the seals.

Control access to seismic mana-crystal deposits before rival factions can exploit them.

Keep the circumstances of the founding collapse hidden until the Cult has gained enough strength to survive the resulting internal crisis.

Hidden plans · GM only

Malakor intends to control the first breach personally, believing that whoever speaks first to the awakened power can direct its wrath.

Several senior Heralds are searching for evidence that the seals contain more than a single primordial force. They hide this from recruits to prevent doubt from spreading.

A quiet faction within the Cult wants to open only a narrow passage, then use the resulting tremors to force surface settlements to abandon deep excavation.

The Fault-Breakers have kept a private record of their sabotage targets. The list includes places selected not for strategic value but to settle old personal grievances.

Smaller secrets · GM only

Some Cinder-Votaries quietly maintain evacuation routes around the very sites the Cult plans to attack.

A Seismic Herald has been altering tremor reports to prevent Malakor from selecting an inhabited gallery as a ritual site.

The Cult’s basalt armor is effective but costly to maintain; several pieces are patched with material taken from old containment structures.

At least one Fault-Breaker has warned Survey Station 4 about an impending attack without revealing their identity.

The Cult does not know whether Terravorus is a being, a title, a mistaken interpretation, or a name inherited from an older belief.

What insiders say · GM only

Trouble inside · GM only

The most serious divide is between the Unsealers, who want to shatter the seals and trust the power beyond them, and the Measurers, who advocate a controlled opening and insist that the Cult first learn what is contained. Malakor publicly treats this as a difference of timing, but his decisions increasingly favor the Unsealers. A second fault line runs between native route-keepers and mercenary fighters. The former want to preserve deep communities; the latter often see a raid as a contract with no obligation beyond payment. Finally, the Fault-Breakers resent the Heralds’ authority to select targets while taking little direct risk themselves.

Crimes · GM only

Plot hooks

5 hooks

1
The Intake Mark
Personal, adaptable to a low-level investigation or rescueReward: Safe passage, local trust, or evidence about the Cult’s internal divisions
A character with a connection to mining or route-keeping receives an anonymous map marking a threatened air-scrubber intake near Survey Station 4. The map’s author asks them to stop the attack without exposing the informant.
2
Unlocking the Third Fault
Regional crisis, suitable for a dangerous mid-campaign operationReward: A settlement’s gratitude, access to route records, or a captured cache of seismic crystals
Fault-Breakers prepare seismic mana-charges near Survey Station 4. If the charges rupture the scrubber intakes, sulfurous gas may fill upper tunnels. The party must identify the correct fault branch, evacuate vulnerable workers, and decide whether to capture or destroy the charges.
3
The Sealed Core Relic
High-stakes relic pursuit involving competing claims and hazardous terrainReward: Custody of the seal-key, a temporary alliance, or evidence concerning the old stone barrier
The Cult sends a raiding party after Ward-Master Korath’s seal-key. The party may defend the Obsidian Vaults, pursue the thieves through unstable passages, or negotiate with a Cult cell that claims Malakor’s intended use of the key is reckless.
4
Awakening of the Basalt Leviathan
Campaign-scale confrontation with severe environmental and moral stakesReward: A chance to avert a catastrophe, uncover ancient containment records, or force a change in Cult leadership
A hidden fault shrine begins to shake as the Cult performs a breach rite. An immense presence stirs behind the stone, identified by the Cult as a Basalt Magma-Titan. The party must stop the rite, find a way to restore the damaged containment, and decide whether collapsing the cavern roof will save the region or entomb nearby communities.
5
The Route That Must Not Be Read
Social and exploratory challenge with consequences for several communitiesReward: A fault-line shortcut, access to a shrine, or leverage over the Cult
Malakor offers the party a secret route through Sub-Levels 2–4 in return for stealing a survey record from a settlement. The record could expose the route-keepers who first met after Kaelen’s discovery, but it may also contain the only reliable map of a failing seal.

Work they offer

1Escort a Seismic Herald to a fault shrine and recover a lost instrument before a rival expedition reaches it.

2Find a missing route-keeper who knows a safe path around an unstable vent.

3Retrieve seismic mana-crystals from a newly exposed seam without triggering a collapse.

4Expose a cell that plans to attack an inhabited settlement, while preserving evidence of the grievances that drove its members to extremism.

5Determine whether a tremor is ordinary geological activity or a sign that an ancient seal is failing.

What gets in the way

Their sabotage threatens the air and water systems that keep vulnerable deep settlements alive, including communities the Cults claim to defend.

Some Seismic Heralds interpret every tremor as a message from Terravorus, even when the evidence points to ordinary geological stress.

The Cults’ cells disagree about whether a seal should be opened carefully, broken outright, or left intact until they understand what lies beyond it.

Malakor’s control of routes and relics has made the movement dependent on one charismatic leader.

A number of members joined to protect their homes from dangerous excavations and may turn against the Cults if they learn the full cost of the plan.

Rumours

1True: The Cult has identified hidden routes close to several ancient seals.

2True: Some Cult members have warned residents before attacks, even when doing so compromised their own plans.

3Partly true: Malakor believes a primordial power is calling to him. Whether he hears an actual voice is uncertain.

4False: Every member of the Cult is an Oread. The network includes Drow, Dao, and people from other deep communities.

5False: The Cult can command all magma and stone in the Under-Roots. Its abilities and knowledge are significant but local, costly, and imperfect.

6Unverified: The name Terravorus may refer not to the entity itself but to an ancient containment protocol mistaken for a living voice.

The Tectonic Cults

The Tectonic Cults

Overview

How it began

How to know them

Standing

What they say they want

What they are doing now

Where it leads

How others see them

People

High Speaker and Core-Herald

Other key members

How they are organised

Relations

Operations

What they do

How they do it

Services for hire

What they can do

What they have

Where they are weak

Territory

Headquarters

Lands they hold

Outposts

Secrets

Plot hooks

Work they offer

What gets in the way

Rumours

Connections

Media

Turn The Tectonic Cults into a sheet