Loose threads How did the serpentfolk use ancient dwarven technology to build their own constructs and control them remotely? Does Srasthadra have access to this knowledge? What is the four-dimensional object involved with the technology? (Also the hole into the ancient mine we didn't explore.)
Participants Cleaner of Bones, Naomi, Russ'Ruk, Plume
Locations the Vault of Doom™ below the Dragon's Tail range
Short summary: Following the reports of Srasthadra's forces acquiring a cache of dwarven constructs to use in their conquest of Watchers' Island, a small group headed by those familiar with the serpentfolk traveled to the vault to put a stop to the source of the constructs, and whatever other machinations they had. Together they slew the serpentfolk inside and destroyed the remaining constructs (which, they learned, the serpentfolk had found a way to remotely pilot after suspension within strange pods), and finally encountered and defeated Atiu, who had been transplanted into a giant clockwork serpent herself. With that, they sabotaged or seized the rest of the technology, research, and materials there to prevent its further use.
Full Report
I'll elaborate on the locations and theory and keep the events simple, because on their face, they were. After Plume organized our group, we traveled four days to the vault which sourced their army, guarded by three aapoph serpentfolk, a zyss, and a clockwork*. We hid the bodies and waited for a coil spy to investigate outside, then stole their keys while invisible and snuck in.
There was a broken, looted museum; the right path led to a classroom they'd repurposed for resting quarters, and a study with a hole in the wall overlooking a large cavern (presumably their means of ingress, and possibly a mine that once fueled the vault), while the left path led to a makeshift canteen with oozes still around, and then an occupied laboratory with some sort of glowing object which shifting in and out of our dimension from within its metal cage(?), lined with vats of liquid housing serpentfolk in stasis who were attached to wires, all of the vats glowing faint green save for one that was orange. After the vault was taken, these were set up by them to control the constructs remotely, somehow, with the orange one corresponding to the clockwork we'd destroyed outside.
Inside were two granitescales checking on the vats and consoles in the room, as well as two bone prophets arguing about the need to report the error with the orange vat so that it would be known to "the Chorus" (likely the one mentioned by the Voice of Atiu in Shuffling Off This Mortal Coil, some inane serpentfolk organization presumably aligned with the entity known as The Weaver), at the cost of Atiu's anger if it was just a glitch. We killed them all before this could happen, but we had to chase after the granitescales, and one of them alerted the four constructs in the next few rooms: three more warrior-types equipped with rifles, and a mage-type** that protested in Aklo when I ripped out its spellcasting core. Following this, at Russ's behest, we organized a ceasefire to speak with them, and this is when we realized what the serpentfolk had done and destroyed their construct bodies.
The final room was barricaded from the inside, and housed Atiu within a large clockwork serpent*** of Srasthadran design, and her bone prophet assistants hurriedly working on the last pieces of her construction; these hailed her as some sort of ascendant being. The construct was powerful, sure, but hastily made, and it was destroyed shortly after the zealots were dealt with. Behind a false wall nearby was the vat with Atiu, who I executed along with the other remaining serpentfolk in the area once we had a moment. She didn't speak about whatever position in or ties to the "Chorus" she had, and as our history is irrelevant now, I don't care to write much more about her. My best diagnosis would be a megalomaniacal mid-life crisis.
There was a large amount of materials they could use to create constructs left in the area, which we took back with us in an attempt to deprive them of further work. Reverse-engineering the vault constructs to make their own is one thing, but how they were able to jury-rig this remote control process so quickly is an open question. With their forces on the back foot and the city at large presumably occupied, an investigation into Srasthadra itself might illuminate more about their capabilities. - Naomi
* Was equipped with water jets that propelled it upwards, a scimitar, and a firearm. Resisted fire. As previously expected, all of the clockworks here were weak to electricity.
** Four-armed, could cast Stinking Cloud and Shield. This type uses a spellcasting focus to cast anything more powerful than a cantrip, and you can steal it to disable them if you're deft. This one's core functioned as a wand to cast Glitterdust.
*** This was a custom job, but they might employ others of similar design. It was worst at dodging physical attacks, was difficult to hit until we broke some of its armor, seemingly wasn't naturally resistant to fire, and was capable of continually shifting to different forms with different attack capabilities: one that could emit a powerful wide-ranging sonic blast, one suited to constriction, and one that could spray a poisonous skin-irritant. Possibly because of its hurried construction (or exacerbated by it), the serpent was vulnerable to being stunned out of the change by precision attacks or electricity at the moment of its shifting, when the internal mechanisms were briefly exposed. The wretch didn't put up much fight after we exploited this.