Citizens of an underwater city have begun abandoning their homes in a trance, drawn toward the otherworldly Batangis Reef. The party must investigate the ancient resting place of an alien creature - and the Asura exploiting its power.
"Neridians from an underwater city near Batangis Reef have begun acting strangely - glazed eyes, mumbling about a 'ruler rising again' - before abandoning their homes entirely. The Helical Archive has contracted you to investigate, partnered with a local Balladeer versed in the sea's ancient history. After a long voyage, you've arrived at the Archive's marine base: a small island atoll directly above the Reef. You are to be briefed by the respected, though eccentric, marine biologist Larimar."
As a one-shot, the Citadel is a simple node - but feel free to expand it into a full Adventure Site! For inspiration, "The Lantern of Wyv" by Trilemma Adventures could fit well. You may incorporate Journey mechanics in too but they are hand-waved here for time.
Set the scene, have Larimar introduce the marine base, then continue:
"All manner of densely-packed, otherworldly flora and rock formations make up this reef. You continue to catch yourself spacing out in their mesmerizing allure."
Long before the shattering of the Sun Machine, this reef has grown here, blood nourishment making it a foreigner to this world. Occasional puffs of thick purple mist come out from various flora.
Passing through requires an Aura Check (or Anti-Hazard Suit) or the character becomes Disoriented. Only the creature's bloodcrystals can cure this effect.
"A colossal skeletal structure and theoretical physiology unlike anything on the Outer World, which is saying something, only pockets of deep purple rock dot its remains."
All that's left is a skeleton and the deep purple rock, which is portions of its blood that crystallized.
Mining requires an Insight Check; failure results in a Wound. Success yields 2 Units of Xeno Bloodcrystals. Let players understand which Aptitude the Check is.
"Open, massive pearlescent doors welcome you into an imposing structure filled with sculptures and architecture plundered far and wide over ages past."
For this one-shot, consider the citadel to be primarily a massive long foyer filled with wonders of the past world before leading into a main chamber where Ophyr awaits on a broken throne.
This Citadel contains hidden writings by scholars of eld detailing the crown's cursed history and being forced to work under The Subjugator's reign.
On successfully taking down Ophyr and recovering the crown:
If Foam's survives, the party gains a Social Bond with her and an invitation to visit Lemuria.
The Coralweave Piercing rests on the Citadel's throne.