Arwen:
The figures are writhing slightly in pain, clutching their grotesquely distended stomachs as they lie on the rocky ground.
One of the guards sees Arwen peering into the torchlight at the figures, and laughs. "This is what happens when the false take the worm. Tiamat knows the truth in our hearts, merc."
The guards who asked for his sword also demands that Arwen turn over his handaxes, and once he does so, another guard escorts Arwen, along with his companions, through the cavern. "Only step where I step; the passages are trapped."
The first chamber they pass through is badly light; the entire right half shrouded in darkness. This chamber leads to a 10-foot drop-off. To the right, broad steps are roughly hewn into a natural stone ramp. The cavern below is carpeted with a profusion of fungi ranging from a few inches high to nearly as high as Arwen is tall. Two paths lead through the fungi: one on the right and one on the left. The guard leads Arwen down the stairs, telling him to not step on the third to last step; it's trapped. Once among the fungi, she leads Arwen and co. along the left path in the next chamber.
The next chambers is large, and empty, save for a few stalagmites and a spear with a pitted blade lying on the floor, by a path to another chamber to the west. The guard and Arwen pass through this one quickly.
The guard leads Arwen through a trapped passage, telling to avoid walking in the middle, and into a chamber split in two. Half is a pit, while Arwen and the guard encounter some kobolds and cultists milling around busily on the upper half of the chamber. The pit is shrouded in shadow, and he can't get a good look at it. The upper half has wooden stairs leading into the darkness, and a rack full of implements: long poles with lassos at the end, leashes and collars, sharp prods, mock weapons and human-sized dummies made of sailcloth. The drake growls and slinks closer to its master, away from the pit.
Picking up the pace, the group passes a cave full of the sounds of reptilian jubilation, and a foul stench of wine, urine and mold assaults their noses. On the stairs leading up to it, the guard points out another trapped step to avoid.
After more stairs up, and then some down, they reach their destination. This chamber has been enlarged and reshaped from its original form. The floor and three of the walls are smooth and stalactites and stalagmites have been polished into gleaming columns. Every surface glistens with moisture, and the air is warm and humid. The flat walls of the chamber are decorated with shallow abstract carvings of dragons. Dragons' tails coil into intricate patterns and knots that flow across the walls. The creature portrayed in the northwest corner stands out: a five-headed dragon, rising from an erupting volcano. Other dragons, which seem dwarfed by the five-headed monstrosity, flock to its side. A small, wooden chest with silver and mother-of-pearl inlays sits on the floor in the corner, in front of the monstrous dragon carving. Above it hovers a ball of inky purple blackness about the size of a large child's ball. Black-purple tendrils emanate from it, and stretch throughout the room. Beyond that, you can see nine blue half-dragons inside. There are two entrances to the room, and there are two half-dragons guarding each. Four more are standing watch over the largest half-dragon of the group, who is in quiet prayer over a corpse with their back turned to the door. A large tendril from the black ball is wandering over the corpse's body.
You are stopped at the entrance by that entrance's guards.
<Why do you dare disturb this ritual,> the half-dragon demands in a hushed voice.
<This one,> the guard replies in equally hushed voice, gesturing at Arwen, <was called for by your master.>
<He called for no such thing.> The half-dragon switches to heavily accented Common to address Arwen, saying "Explain this interruption," <[pink worm meat].>