Battlemap
The Keepwall Sapper's Run
Beneath Ravenbrook, the drowned stones count down to ruin.
Beneath Ravenbrook Keep's north curtain wall lies a drowned network of maintenance galleries, built to carry water, heat, and leyline power through the fortress foundations. Now tunnel engineers have converted the old conduits into a demolition grid, and their arc-forges are preparing to tear open the wall from below. The adventurers must trace the sabotage, silence the soul-energy, and stop the keep from being breached.
Cold runoff trickles through ankle-deep water, carrying the smells of wet stone, lamp oil, and bitter alchemical fumes. Torchlight shivers across green-black masonry while fractured runes spit blue sparks, and every distant clang from the arc-forges trembles through the flooded floor. Beneath it all, something whispers from the soul-charged conduits, counting down.
☠ Threat
Tunnel Engineer Varrik Pell, a master sapper serving the Obsidian Tribunal, directs the operation from the flooded forge chamber. He has planted soul-charged demolition charges throughout the old maintenance grid, using bound spirits to amplify each blast. If the party delays, Varrik completes the sequence, collapses the north curtain wall, and opens the buried leyline junction to Tribunal extraction teams waiting outside the keep.
History
The tunnels were carved into the foundations of Ravenbrook Keep by its first engineers, who diverted underground water and ley pressure away from the curtain walls. After the Great Divine Schism, keep wardens sealed the deepest shrine and abandoned several maintenance galleries. Centuries later, Obsidian Tribunal agents rediscovered the network, occupying it as a covert sapping station and repurposing the old runes to charge soul-bound demolition devices.
Encounter Table
CRA drowned corpse wrapped in Tribunal chain drifts through the water, its mouth opening whenever a rune sparks.
A mass of animated cables and broken tools creeps along the walls, clicking like insect legs beneath the water.
A pale spirit in the uniform of a Ravenbrook engineer carries a lantern that shines through stone. It may warn the party, mislead them, or beg for release.
A black-robed Tribunal retrieval agent searches the tunnels for Varrik's notes and the soul engine's prism, moving silently through the deepest water.
Rumours & Whispers
The north wall leaks black water whenever someone dies inside Ravenbrook Keep.
A Tribunal engineer has been buying condemned prisoners from local magistrates, then sending their names beneath the keep.
Old soldiers claim the tunnels were built over a sleeping emerald dragon, though the fortress records deny any such foundation.
The keep's arc-forges have begun working by themselves at night, even though their operators vanished weeks ago.
A sealed shrine beneath the wall still answers to the first engineers of Ravenbrook, but only if the intruders come to repair rather than plunder.
Quest Hooks
Quest giver: Captain Maelin Voss, commander of Ravenbrook Keep's engineers
Ravenbrook's north wall shudders during the night, and guards report blue sparks rising through the stones. The party is ordered to investigate before the foundations fail.
500 gp, a fortified room in the keep, and a favor owed by the garrison
Quest giver: Sergeant Elian Rusk, a shaken prisoner who defected from the Tribunal
A captured Tribunal courier carries a partial map of the tunnels and a list of soul names, including a missing Ravenbrook officer. The party must find the officer before the charges consume the final spirits.
A radiant seal that grants advantage on one future check against Tribunal magic
Quest giver: Sister Hestara Vale, priest of the Celestials of Dawn
The Obsidian Tribunal seeks the buried leyline junction beneath the keep, while Ravenbrook's priests want the old shrine restored. The party must decide whether to preserve the system, claim its energy, or destroy the unstable network.
A Dawnwardens' writ, sanctuary at allied temples, and a blessed repair kit
Corridor Notes
Waterlogged support braces lean beneath the ceiling, their joints swollen and split. A heavy impact or creature moving more than 20 feet in a turn may trigger a collapse, forcing a DC 14 Dexterity saving throw or dealing 3d8 bludgeoning damage in a 15-foot cone.
Moss-choked fractal runes pulse beneath the waterline. A DC 15 Intelligence (Arcana) check reveals that they feed power toward the demolition charges, while a DC 18 Intelligence check can tune one down during combat.
Narrow maintenance alcoves conceal rotted benches, sapping tools, copper wire, and sealed flasks of alchemist's fire. A DC 13 Wisdom (Perception) check locates each cache.
Thin silver bubbles rise from cracks in the floor whenever the soul-charged charges gain power. Their direction points toward Room 2, though the bubbles sometimes reverse as the shrine in Room 5 resists the sabotage.
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