Here are some ideas for locales in The Onyx City surface.
A vast, flat expanse of perfectly smooth onyx, etched with a complex, luminous grid pattern that faintly glows at twilight. Its purpose is unclear, but it feels like a giant, silent circuit board.
Wide, shallow channels cut into the onyx ground, lined with small, metallic nodes at precise intervals. These paths crisscross the city, hinting at an intricate, now-silent, data or energy network.
An enormous, perfectly flat plaza constructed from highly polished, reflective black onyx. It acts as a giant mirror, reflecting the sky above with unsettling clarity, and rumored to be a landing zone for aerial craft.
Beyond the main city structures, vast fields where countless unpolished, jagged onyx obelisks of varying heights rise from the ground like teeth. They appear naturally formed but are arranged with an unsettling, purposeful irregularity.
Several austere, windowless towers of stacked onyx segments, each segment featuring intricate, overlapping vents. A faint, sterile scent sometimes drifts from them, suggesting a past role in atmospheric control or waste processing.
A sprawling, multi-tiered structure of dark onyx, featuring massive, unblinking lenses and crystalline focusing arrays aimed at the sky. Its purpose was clearly to peer into other dimensions or monitor cosmic phenomena related to the Skein’s properties.
A heavily reinforced, windowless onyx structure, its entrance sealed by a massive, seamless door. The air inside is unnaturally still, and any magical effects or innate abilities brought within feel muted or suppressed, a place perhaps used to safely contain volatile energies or beings from the Skein.
Clusters of irregular, sharply angled onyx formations that resemble abstract, monstrous faces or twisted limbs. When the wind blows, they seem to produce faint, inhuman whispers or sighs, a chilling echo of the Greys’ silent presence, perhaps residual psychic impressions from their travels through the Skein.
Wide, open channels, deeply carved into the onyx streets and walls, lined with intricate, non-metallic nodes. These pathways once pulsed with collected magical energy, now silent, but still radiating a faint, residual chill, suggesting a system for channeling raw Skein energies.
Several large, collapsed onyx domes, their transparent (now fractured) sections revealing sterile, dust-filled interiors. Petrified, alien flora and fauna stand perfectly preserved within, remnants of the Greys’ scientific endeavors to adapt life to varied Skein-accessed worlds.
Sections of the city where rows of naturally occurring crystalline formations (possibly outgrowths of the onyx itself) have been allowed to grow, but are shaped and pruned with unnatural, geometric precision.
Small, black, reflective onyx pools, where looking into the perfectly still surface can sometimes induce strange, fleeting images or emotions that aren’t one’s own, residual psychic imprints.
Small, sealed onyx alcoves or rooms, clearly designed to house specific, important artifacts or samples collected from various worlds accessed via The Skein. They are now empty but radiate a faint sense of lingering importance.
Tall, rectangular onyx slabs, scored with countless tiny, non-repeating glyphs across their surfaces. They feel like inert storage devices, holding unimaginable quantities of Grey knowledge or research data.
The pinnacle of the Aetheric Observatory (from a previous list, now a single prominent feature). It’s a massive, multi-faceted onyx lens at the very top of the tallest structure, seemingly capable of peering into distant galaxies or the chaotic energies of The Skein. It’s designed to withstand immense cosmic forces.
A heavily reinforced, central onyx complex of interlocking blocks and spires. This is the primary control center for the city’s vast systems, its walls covered in silent, intricate panels of non-human design. Access is likely sealed or requires Grey-specific methods.
A large, partially collapsed onyx dome. Its interior walls are still covered in faint, luminescent glyphs forming complex star charts and constellations, hinting at the Greys’ advanced understanding of the cosmos.
A series of precision-cut onyx rings and platforms arranged in a specific, sprawling pattern across an elevated section of the city. These were likely used for aligning or calibrating their understanding of different planes or dimensions accessed through The Skein.
A wide, open shaft with remnants of internal scaffolding or mechanical arms clinging to the onyx walls. It clearly served a functional purpose for large-scale repairs or installation in the levels below, rather than direct personnel transport.
A low, unassuming archway cut into a natural rock face or the base of an onyx building, perfectly sealed with a featureless onyx block. It suggests a more traditional, though now inaccessible, entrance to subterranean living or storage areas.