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The Obsidian Citadel

Emerald light pulses through the veins of a dying sky as the cannon hums with god-slaying power.

40 roomsLaboratorydeadly

A colossal vertical spire of dark, shifting metal that pierces the atmosphere, crackling with unnatural lightning. Neon green circuitry traces the walls of every chamber, illuminating the laboratory of the Shadow organization's final doomsday project.

The air smells of ozone and heated copper, vibrating with a constant low-frequency hum. Lighting is dim, provided by flickering green floor-strips and the occasional flash of external lightning storms. Temperature varies from freezing in the lower shafts to sweltering heat near the power conduits.

☠ Threat

The Jupiter Cannon's core is maintained by High Architect Vane and the corrupted AI NEXUS. While Vane oversees the firing sequence from the spire's peak, NEXUS manipulates the Citadel's gravity and security protocols. Every moment the party lingers, the cannon draws closer to full charge, threatening to vaporize human civilization from the safety of the void.

History

Constructed over two decades by the Shadow collective, the Citadel serves as the housing for the Jupiter Cannon. Originally a weather station, it was retrofitted with alien tech to harness planetary storms for orbital strikes. The facility is now a fully automated slaughterhouse, managed by a fragmented AI that views biological life as a contamination to be purged before the weapon's final countdown.

Encounter Table

CR
1/8CR
Maintenance Dronex1d4

Small robots with welding torches that try to 'fix' intruders.

1/2CR
Shadow Scoutx1

A stealthy cyborg that attempts to radio back for reinforcements.

1CR
Malfunctioning Sentryx1

A large bipedal robot that fires suppressive sparks wildly.

Rumours & Whispers

1

The Jupiter Cannon was not built by humans; the Shadow found the blueprints in a crash site.

2

The Architect Vane is more ghost than man, his consciousness spread across the Citadel's servers.

3

If you wear the color emerald green, the automated drones might think you're a high-ranking official.

4

The core of the spire is sinking into the planet, and the cannon's firing will accelerate the collapse.

5

A hidden resistance member is trapped on the storage levels, waiting for rescue.

Quest Hooks

1
Operation Midnight FallInfiltration

Quest giver: Dr. Aris

A group of scientists needs someone to break in and insert a virus into the Citadel mainframe.

1,000 gp and high-tech weaponry.

2
The Stolen HeirloomRecovery

Quest giver: Chancellor Reed

An ancient crown was stolen from a nearby kingdom and is being held in the General's Vault.

The crown's weight in gold if returned safely.

Corridor Notes

All primary hallways

Flashing emergency lights that cycle from red to green when an intruder is detected.

Connectors between logistics and assembly

Magnetic rails on the ceiling used by transport drones to carry crates overhead.

Exterior-facing walkways

Floor-to-ceiling glass windows showing the terrifying height and the storms outside.

Visual sheet

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