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The Blackglass Line

The rails remember every passenger, and something beneath them is still hungry.

13 roomsAbandoned Subwaydeadly

The abandoned Blackglass Line descends beneath the city in a loop of ruined platforms, service tunnels, and shrines built into the station walls. Monstrous animals have claimed the dark, but something intelligent has trained them, fed them, and taught them to guard the sealed terminus below.

Cold, stale air rolls through the tiled tunnels, carrying rust, wet stone, and the musky stink of nesting beasts. Flickering blue witch-lights pulse along dead platforms while distant rails groan without trains, and every echo seems to arrive from the wrong direction.

☠ Threat

The line is ruled by Mother Gristle, an enormous pale tunnel boar swollen with eldritch growths. She has learned to recognize old conductor tokens and uses the station's surviving signals to drive lesser beasts toward intruders. Her presence is felt through vibrations in the rails, sudden power surges, and the growing certainty that the tunnels are her territory.

History

The Blackglass Line was built by the Veyr Consortium to move ore beneath the city, but its engineers uncovered a temple dedicated to the Undertrack Mother, a colossal burrowing beast. Rather than abandon the project, they incorporated the temple into the stations and used trained animals as wardens. When the final ritual failed, the line was sealed, leaving passengers, workers, and beasts trapped in the dark.

Encounter Table

CR
1/2CR
Blackglass Rat Packx2d6

A pack of black-eyed rats carrying scraps of transit tickets and bits of bone.

1CR
Signal Hyenax1d3

A scarred hyena with metal tags fused into its hide and a laugh that echoes through adjacent tunnels.

2CR
Rail Bearx1

A blind cave bear that follows vibrations through the rails and attacks anything moving near a platform.

1CR
Track Lizardx1d4

A huge tunnel lizard with a lamprey mouth and oil-black scales.

Rumours & Whispers

1

A ghost train still arrives beneath the city, but every passenger who boards comes back missing their shadow.

2

The old subway beasts are not wild. Someone rings a conductor's bell to send them hunting.

3

A treasure vault lies under the last platform, guarded by a boar bigger than a carriage.

4

The Blackglass Line was sealed after an entire train was swallowed by the earth.

5

The city's founders made a bargain with something underground, and the bargain is coming due.

Quest Hooks

1
The Line That Should Stay ClosedInvestigation

Quest giver: Mara Venn, anxious city engineer

A city survey crew vanished while reopening an old subway entrance, and their foreman's brass token was found in a gutter nearby.

300 gp, official salvage rights, and a favor from the city works guild

2
The Bell Beneath the HouseRescue

Quest giver: Orren Vale, frightened spice merchant

A merchant's child is hearing a subway bell beneath their house and sleepwalking toward the cellar each night.

A silver warding charm and 250 gp from the merchant consortium

3
The Undertrack HeartRelic Hunt

Quest giver: Sister Caldris, priest of the Lantern Road

A shrine keeper believes the abandoned line contains the lost Heart of the Undertrack, a relic that can heal a dying district.

A blessed healing relic and sanctuary at the temple

Corridor Notes

Between Room 1 and rooms-1 through 4

Old station signs hang crookedly above the tunnels, their letters rearranged by claw marks into warnings such as RUN and BELOW.

The main tunnel outside Room 4

A third rail intermittently spits blue sparks. Metal objects dragged across it attract the attention of creatures deeper in the station.

The tunnel between Room 6 and rooms-11 and 12

Puddles of oily water conceal paw prints larger than a wolf's, all pointing toward Room 6.

Near the locked door to Room 11

Emergency telephones occasionally ring, though their cords lead into sealed walls. Answering one produces breathing and a distant scratching sound.

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