Wealday, 13 Kuthona, 4733
Having dispatched the ogres sabotaging the dam, the Rune Wardens venture out onto Skull’s Crossing, only for the dam to shudder beneath them. A new crack emerges in it and a gush of water pours out. An enormous, terrible creature with tentacles tries to climb through the gap. It is Black Magga, the legendary scourge of the Storval Deep!
Marcus hurls a lightning bolt at it, to no effect. Zavian figures out a plan to harm the creature and runs off at supernatural speed. Astrid runs up to attack it, but is grappled by a tentacle. Lea goes after her. Amelia starts inspiring courage.
The monster belches a poisonous cloud onto them that confuses Astrid, Marcus, and Amelia. Lea dodges a tentacles and runs up to attack the tendrils grasping Astrid. Astrid babbles incoherently, Marcus and Amelia injure themselves and each other.
Lea smashes the tentacle grasping Astrid. The creature freaks out and flees. Zavian apparates into the air above, standing atop a stone plug he crafted. It falls into place, sealing the crack in the dam.
The disturbance rouses several trolls from the central structure on the dam. One tries to leap across, but slips the landing. Another troll rips a door off its hinges and hurled it at Zavian.
The adventurers recover from the confusion. Amelia charms one of the trolls, but can only communicate through gestures. She gestures for it to leave.
The runtish troll leaps out to attack Zavian, but falls down below, then climbs back up. Zavian and his spiritual ally go after the Troll throwing the door. The charmed troll moves to attack him. Amelia isn’t able to convince him to leave.
Zavian coup de graces the held troll, but the creature’s regeneration keeps it alive. Lea makes her way over to bash it with fire. The other charmed troll leaps at Zavian but tumbles off the dam.
The adventurers search the troll room, find some hidden loot and a warning about “Big Papa Grazuul” over the stairs down. The party descends 150 feet and finds a room with an algae covered pool and multiple doors. They decide to open the side doors, starting with the one on the left.
The leftmost chamber contains a model of Skulls Crossing, and a pile of skulls. Lea and Marcus move up to investigate. This causes the pile of skulls to assemble into a scorpion and advance. Lea channels positive energy, but realizes that the scorpion is a construct.
In the central chamber, Big Papa Grazuul lunges out of the algae pond to attack Zavian. Meanwhile, the scorpion construct seizes Lea in its pincers.
Whirling her double-bladed sword Echo, Astrid moves up to the aquatic troll Grazuul and takes him apart. Literally.
In the side chamber, the scorpion pins Lea to the ground and raises its shears. Marcus stabs it but his ranseur gets stuck. Zavian uses dimension door to evacuate Lea. The Rune Wardens surround the construct and hammer it. After the scorpion is destroyed, Lea keeps trashing it.
The party continues their investigation of the dam’s interior, finally coming to a chamber with two large cells with big circles of glowing runes scribed on their floors. In one cell, a pile of crimson ash sits in the center of the circle, while in the other a dead devil lies in the circle.
Approaching, they discover the devil isn’t dead at all. It has been trapped here for 10,000 years and begs for release, promising to offer valuable secrets about the planes. It tells Zavian that the aasimar is more than he appears, and this catches the cleric’s interest. He negotiates with the devil, while Lea protests, unable to understand their conversation.
Marcus figures out that the circles were leeching power from two devils in order to operate the dam’s overflow, until one of the devils was finally drained to death. Now there is insufficient power to operate the overflow. But if another creature steps into the empty circle, it will be drained instead and the dam should operate. Lea volunteers and Marcus runs off to use the model in the scorpion chamber to operate the dam.
Still unsure whether to take the devil’s offer and release it, Zavian appeals to Abadar for guidance and gets the sense that would be a Bad Thing. The cleric angrily walks out of the room as the overflow is activated and the pit fiend is drained to death.
Zavian heads up to the top of the dam to sulk, where he is visited once more by the strange dog he keeps seeing. This time, the dog speaks to him, chastising him for being so tempted by the devil. The dog reveals itself as a hound archon and explains that he once fought alongside Zavian back when the latter went by a different name as a celestial serving in the Dawn Bringers.
The hound archon explains that Zavian’s foolish deal with a contract devil damned his lover Elsevina and saw him banished to live out a mortal life on Golarion. He barely avoided repeating that mistake today. The hound warns him that the waters that spilled from the dam have imperiled Turtleback Ferry.