The Science of Halidom

The science behind the world of Halidom.

Halidom doesn't run on magic. Its people survive through systems adapted from old technology: biology, engineering, chemistry, and atmospheric science bent into new shapes after the Great Weathering broke the world.

What follows is how it works. And where the ideas came from.

The Limestone Seabed

Halidom Wasn't Built Where it is by Accident.

The region sits on an ancient seabed that is rich in limestone, mineral salts, sand deposits, and buried organic material left behind by marine ecosystems that died long before the Weathering. These became the raw materials for rebuilding.

Limestone could be cut into building stone, processed into mortar and cement, and fed into high-temperature kilns. Heated with sapfire, those kilns ran hot enough to forge iron and copper, refine metals, and melt sand into glass.

The seabed also contained trace mineral salts that interfere with the Bloom's ability to regulate water absorption. Salt slowed the spread near the city's foundations. Not a cure, but enough to buy time.

Stone for construction. Sand for glassmaking. Metals for machinery. Fuel beneath the ground. Enough salt to hold back biological collapse. The location allowed Halidom to survive when most other settlements didn't.

Rooted in: Limestone quarrying, ancient seabed geology, lime mortar and cement production, glassmaking from sand, kiln metallurgy, salt-rich soil chemistry.

Sapfire

Fuel Grown from Living Organics

Sapfire is a volatile biofuel refined from engineered organic material and ancient Bloom reserves buried beneath the city.

Many plants naturally produce flammable substances—pine resin, eucalyptus oils, tree sap, and terpene-rich compounds. These materials store chemical energy that burns with intense heat. Researchers today are developing plant-based fuels as alternatives to petroleum.

The Bloom was engineered to grow rapidly while storing massive amounts of energy inside its root systems. Over time, underground reservoirs formed beneath the old seabed. Those deposits became sapfire.

The Skywoven still harvest small amounts to power machinery and keep their airships aloft. The supply is finite. That fact drives much of the story.

Rooted in: Pine resin and pitch, turpentine chemistry, biofuel research, plant-derived hydrocarbons.

Glow-Lichen and Gleamroot

Living Light

Certain fungi glow through chemical reactions involving light-emitting compounds mixing with oxygen. This faint light, sometimes called foxfire, appears on rotting wood deep in forests.

Halidom expanded the idea through engineered lichens and mosses designed to retain moisture, glow continuously, survive underground, and spread across stone surfaces. The Rooted cultivate glow-lichen inside sealed glass jars. Portable light sources that require no fire or electricity.

Rooted in: Bioluminescent fungi, foxfire, glowing algae, symbiotic lichen ecosystems.

The Cloudline

A Machine Built into the Sky

Some parts of the world use specialized mesh systems to pull drinking water directly from fog and humid air. Entire forests survive by collecting moisture from clouds instead of rainfall.

The Cloudline scales that concept into a massive engineered canopy. It condenses atmospheric moisture, redistributes rainfall, regulates temperature, and stabilizes the environment around Halidom. Its rain cycles behave more like breathing than weather.

Rooted in: Fog-harvesting systems, atmospheric water generators, cloud forests, climate engineering.

Salt Cycles

Controlling the Bloom

Salt can prevent many plants from absorbing water properly. High concentrations damage root systems. Farmers and civilizations throughout history have used salt to suppress invasive growth and sterilize unwanted vegetation.

Trace mineral salts carried through the Cloudline help suppress the Bloom's expansion. The Bloom struggles to regulate water absorption in salt-rich environments, causing sections of its vascular system to weaken or collapse.

Over generations, food crops in Halidom were selectively cultivated to tolerate low levels of salt exposure. Fruit trees, moss grains, climbing legumes, root vegetables, and several engineered orchard plants grown within the towers adapted well enough to survive where the Bloom couldn't.

A fragile balance. Enough salt to suppress the Bloom. Not enough to destroy the food supply. The Cloudline's mineral cycles became essential to holding that line.

Rooted in: Soil salinity science, salt-resistant agriculture, halophyte plants, irrigation mineral cycles, selective crop adaptation.

Lift Systems

Moving a Vertical City

The towers use realistic mechanical transportation: counterweights, pulleys, cable systems, braking mechanisms, and pressure-assisted shafts. Some higher tower lifts use heated chambers powered by sapfire, creating buoyancy through hot air and pressure differences.

Older freight lines are still operated manually by rope crews using balanced systems stretched between towers.

Rooted in: Counterweighted elevators, mine shaft lifts.

Thermal Updrafts

The Hidden Weather Inside the Towers

Heat differences between buildings, stone surfaces, sunlight, and wind can create strong updrafts and shifting air channels. Halidom's vertical design magnifies these effects dramatically.

Climbers and glider crews learn to read these currents — travel efficiently, move cargo, navigate between towers, and conserve energy during flight. The Skywoven uses thermal currents above the old seabed to reduce fuel consumption during long journeys.

Rooted in: Urban heat island effects, thermal soaring physics, convective airflow, wind tunnel effects, passive ventilation systems.

Climber Lines and Rigging Fiber

Rope Grown from Engineered Organics

The towers depend on an enormous network of ropes, cargo cables, and suspension systems. Many are made from engineered plant fibers descended from early Bloom research.

Natural fibers like hemp, flax, jute, sisal, and certain climbing vines can produce incredibly strong rope. Some natural-fiber ropes preserved in dry environments have survived for decades.

Halidom expanded this through engineered vascular plants designed to grow long, continuous fibers, flexible internal strands, and extremely dense cellulose structures. Lightweight, strong, and resilient against moisture and temperature changes.

Certain climbing lines in the towers have remained in service for generations through constant repair, splicing, and oiling. The irony: many of the strongest rigging materials originated from the same biological engineering that eventually produced the Bloom.

Rooted in: Hemp rope, flax fibers, cellulose strength in plants, bioengineered materials, natural fiber preservation.

Skywoven Airships

Floating Through Heat and Buoyancy

The Skywoven airships stay airborne through lighter-than-air flight. Heated gas chambers, lightweight materials, buoyancy control, and carefully balanced structures. Sapfire provides the heat to keep lift chambers warm during long flights.

The vessels function more like interconnected dirigibles than traditional aircraft.

Rooted in: Zeppelins, dirigibles, thermal airships, lightweight composite structures.

Solar Veils

Harvesting Light Above the Clouds

The upper towers use large solar collection surfaces positioned above the thickest layers of the Cloudline. Because much of the lower city lives beneath haze and filtered sunlight, the highest districts became critical energy collection points.

Thin reflective films and photovoltaic materials gather solar energy and redirect power downward through tower systems. The technology evolved over generations as the city adapted to a darker atmosphere.

Rooted in: Solar panels, thin-film photovoltaics, reflective energy systems, high-altitude solar collection.

Resonance Networks

Cities Tuned Like Instruments

Many systems in Halidom rely on sound, vibration, and resonance instead of wireless communication. Harmonic frequencies travel through the towers themselves. Repeaters strengthen signals across distances. Specific tones interfere with the RootBane's ability to navigate and fly.

Large structures naturally vibrate from wind, movement, temperature shifts, internal machinery. Halidom's builders turned that liability into infrastructure. Some tower materials were intentionally engineered to carry sound efficiently, making the city itself a broadcast system.

Many insects rely on vibration and environmental signals to orient themselves. The harmonic network exploits this by overwhelming the RootBane's flight coordination and keeping swarms from surfacing near populated regions. The system doesn't destroy the insects. It disorients them. Without the network, the RootBane begin emerging from underground tunnels and dormant hive systems.

Rooted in: Resonance physics, acoustic engineering, tuned mass dampers, insect vibration sensitivity, structural resonance engineering, sonar systems, ultrasonic technologies.

Whisper Nodes

Tiny Machines Powered by the Environment

Whisper Nodes are small distributed sensors embedded throughout Halidom. Instead of relying on large electrical grids, they harvest tiny amounts of energy from vibration, pressure, movement, heat, and resonance. The network continues operating even after larger systems fail.

Modern researchers are already developing technologies that work this way. Energy harvesting and ultra-low-power electronics.

Rooted in: Passive wireless sensors, environmental monitoring, energy harvesting electronics, distributed mesh networks.

Mirror-Slates

Memory Stored on Reflective Surfaces

Mirror-slates are portable reflective devices capable of storing visual records, diagrams, messages, and fragments of old archives. They rely on layered light-reactive materials that preserve information through changing reflective patterns — not modern screens.

Older slates degrade over time. Distortion, flickering, incomplete playback.

Rooted in: E-ink displays, optical memory systems, reflective display technology, holographic storage research.

Shellhorns

Communication Through Sound

Shellhorns are acoustic instruments used throughout Halidom for communication across towers, scaffolds, and valleys. Different tones and rhythms carry specific meanings: weather warnings, lift signals, emergencies, navigation markers, shift changes.

Low-frequency sounds travel well through fog, mist, and stone corridors, making shellhorns reliable even when visibility drops to nothing.

Rooted in: Fog horns, conch shell instruments, resonance acoustics, long-distance sound propagation, maritime signaling.

Glyphs

Stories Stored in Symbols

Many ancient cultures used symbols to preserve navigation routes, engineering knowledge, oral history, and environmental warnings. Halidom's glyphs evolved into layered symbolic systems capable of storing harmonic tuning instructions, historical records, structural diagrams, and stories passed between generations.

Some are designed to be understood visually, even by people who can't fully read them.

Rooted in: Petroglyphs, runes, symbolic storytelling, mnemonic systems, geometric information encoding.

The Bloom

Runaway Biology

The Bloom combines aspects of parasitic vines and genetically engineered organisms. It was created to address food shortages, energy production, and rapid regrowth after environmental collapse. Instead, it spread beyond control and destabilized entire ecosystems.

Rooted in: Kudzu overgrowth, harmful algal blooms, synthetic biology ethics, invasive ecosystem collapse.

Bloom Caverns

Ecosystems Beneath the Seabed

Deep beneath Halidom lie ancient caverns carved out by centuries of uncontrolled Bloom root growth. These underground systems behave almost like living ecosystems that recycle moisture, trap gases, generate heat, and sustain unusual fungal and insect life. Some remain biologically active long after the surface world changed.

Rooted in: Cave ecosystems, underground aquifers, root communication systems, geothermal cave environments.

RootBane

Engineered Predators

The RootBane were engineered to suppress and consume the Bloom. Real ecosystems sometimes use biological controls—introducing one organism to control another. These systems can work, but they can create dangerous imbalances if they spread too far.

The RootBane burrow through Bloom root systems and consume underground growth. Harmonic frequencies help disorient them and keep swarms from navigating effectively near populated areas.

Rooted in: Biological pest control, predatory beetles, engineered ecosystem intervention, invasive species management.

Dormancy Cycles

Waiting Beneath the Surface

Many organisms in Halidom survive through long dormant periods triggered by environmental conditions. The RootBane are the most dangerous example, but they aren't unique.

Some insects, spores, seeds, and microorganisms can remain inactive for years waiting for moisture, warmth, vibrations, or chemical changes. Certain cicadas spend more than a decade underground before emerging.

The damaged ecosystems beneath Halidom are filled with organisms adapted to survive collapse by waiting longer than everything else.

Rooted in: Cicada emergence cycles, seed dormancy, hibernation biology, spore survival systems, desert insect adaptation.

Salt Gardens

Farming After the Great Weathering

After the Great Weathering, much of Halidom's surviving soil contained elevated mineral salt levels from the Cloudline's atmospheric cycles. Farmers selectively cultivated crops capable of surviving in trace salt conditions: salt-tolerant fruit trees, climbing legumes, grains, and engineered root vegetables adapted to difficult soil.

Too little salt and the Bloom spreads. Too much and the food supply collapses. Maintaining the balance became essential.

Rooted in: Salt-resistant crops, soil salinity adaptation, irrigation mineral management, desert farming systems.

Maintenance Culture

Why Halidom Still Survives

The city continues functioning because generations of people learned how to repair old systems, adapt broken infrastructure, recycle materials, and preserve knowledge. Many technologies in Halidom are old, repaired repeatedly, and only partially understood. They keep working because people keep maintaining them.

Rooted in: Infrastructure maintenance engineering, repair cultures, circular economies, adaptive reuse, long-life industrial design.