I counted nine shadows gathering beneath the reef's cracked spires, ten with my own. A single blue beacon pulsed overhead, its rhythm slower than normal, as though the reef itself took shallow breaths after the aftershock. Tide-mist drifted in ragged veils, catching on the broken arches where once-bright banners now hung in tatters.
Yera's voice carried across the water. "Form up." It was not loud, yet everyone heard. Four Watchers fell into a shallow V, their spears polished and rune-checked. Opposite them four Exile scouts drifted in pale cloaks, mirrored shields tucked under one arm. The tension between the two groups felt like a stiff current, but no one voiced it. We all knew why we were here.
She continued, "Our target is the conduit grid feeding the three dormant drills. Countdown to possible re-activation, thirty-two cycles." Rejah flashed the number on her slate. "We disable them or they wake."
Veshra glided forward, cloak shimmering silver in the beacon glow. She held up two fingers. "Two exits," she reminded us, pointing to her map. "Primary up-shaft collapses if charges over-detonate. You must follow my route markers if that happens." She did not need to add trust me, yet I saw several Shellguards exchange wary looks.
When their eyes shifted toward me, I tapped the seed-pearl at my belt and let its teal light ripple across my scales. "Balance, remember," I said. "Strength guided, not forced. We move as currents of the same reef." Shellguards straightened. An Exile scout named Rilan touched a pendant at her throat, a small shard of broken coral, and nodded in silent agreement.
Yera swept her spear in an arc. "Check weight packs, seal helm slits, and keep your glow low. We descend in one."
The first change hit like crossing an unseen wall. Heat seeped into my fins, subtle at first, then insistent. Water here felt thicker, laden with mineral dust that grated along the edge of each gill plate. I slowed my breathing, pulling shallower draughts so the thin water could still scrub enough oxygen for muscle. Even so, my head buzzed softly at the edges, the beginning of hypoxia.
Ahead, fissures glowed amber, thin seams in black basalt that pulsed faint light. Every time one of us passed near, the water shimmered, bending straight lines into wavering mirages. It was beautiful and unsettling, a reminder that the trench's bones ran hot while our bodies depended on cold.
Veshra drifted beside me. "Mind the shimmer," she murmured. "Close cracks distort distance. You think a ledge is a handspan away, then find it half a body-length instead." She demonstrated by flicking a fingertip; the ripple bent oddly, returning at a skewed angle.
My left fin brushed a plume of warmer water. It did not burn, but it carried so little oxygen I coughed on instinct, forcing a harder gulp through my gills. The new organ responded with a burst of warmth, pushing blood faster. I felt the pearl at my belt flare briefly then dim, as if reminding me it could not rescue me every time I overexerted.
We paused at the first alcove, a hollow pocket just broad enough for the ten of us. Rejah ignited a low-light rune. It painted the basalt walls in muted blues, outlines of hexagonal conduit etchings shining where tools had carved stone smoother than any natural current could. She tapped three fingers, then folded them, a silent thirty cycles left. Time slipped fast in the dark.
Yera surveyed us. "Drink nutrient vials, one half-measure. We will not have breath to eat below." I unclipped a small crystal tube, squeezed bitter gel into my mouth, and let it spread down my throat with the water. The gel warmed, giving a fleeting spark of energy before settling into my gut like dull lead.
A Shellguard named Darun leaned close. "Never swam in heat water before," he admitted, voice tight. He was broad-shouldered, proud, yet the thinness stung him too. "Feels like breathing dust."
"Keep your motions small," I murmured back. "Guided flow, not force." I shaped a sample spiral between us, no more than a child's toy, and let it collapse. "The water is half-asleep down here. Treat it kindly and it will move."
Darun nodded, determination firming in his eyes.
The next stretch of tunnel narrowed to a stone throat. Heat shimmer made distance deceptive. I flicked gentle currents ahead, feeling for eddies. One plume of steam burst without warning, shooting molten grit. Instinct flared, my spiral shield formed, but smaller, precise, tugging the plume upward through cracks in the ceiling rather than blasting it backward onto the squad. The maneuver still hurt; warmth flooded my veins, the organ's drumbeat accelerating. Beneath my harness the pearl flickered from teal to pale sky, dimming quickly once the burst passed.
Yera gave a small nod, an acknowledgment that I had not overspent. We descended again.
Metallic clangs rang ahead. Yera flattened to the wall, signaling halt. We drifted to the ledge and saw the engineers. Now, from above, I could smell a faint tang, like rain on hot rock—every time one of their gauntlets vented mana. Their knock language echoed up to us: three sharp, two slow, one long. Rejah, studying the rhythm, whispered, "They log pressure codes then request rune heat. Afraid of overseer check."
Fear. Even the invaders tasted it here. The thought sparked a bitter twist of empathy, but purpose remained.
We formed the pincer. Veshra glided like moonlit seaweed down the right flank, while I slipped left. Each stroke cost more breath. I guided water quietly around my legs to muffle the swirl of silt. When Yera launched forward, the fight felt quick and brutal, yet the heat made every movement sluggish, each strike heavier. Sparks kissed the water when Yera's spear severed elbow runes, and the plume of steam that followed my spiral hissed loud enough to echo.
When the last engineer sank to the floor, I stared at its cracked gauntlet. The pale organ within still pulsed faintly, as if unaware the body around it had died. I tore my gaze away before guilt could choke me. "Move," Yera urged, and we obeyed.
The conduit grid came into view like a glowing cage. Pipes crossed and re-crossed, each thin layer of orange light outlining where stolen organs fed endless loops of power. I drifted closer, compelled by the pulse I felt in the water. Every organ seemed to call out, tiny flickers of life that should have ended but had not. Rage simmered beneath my fatigue.
Rejah and her partner worked with purpose. They planted crystalline charges at nodal joints, hands steady despite the stifling water. "Eight minutes," she said. Yera formed a semicircle defense, and vibration thrummed along the stone. Sentinels.
We braced. Orange eyes erupted in the tunnel mouth. Each sentinel was a living weapon, yet also eerily silent. Their first charge sent ripples through the water strong enough to jolt the floor. Yera met one, blades clashing, sparks spraying. I shaped a vortex, coiling the water around me. The heat made it sluggish, but I tightened the flow, drawing in cooler currents from cracks higher up. The vortex slowed a sentinel's swing long enough for Veshra to blind it with her mirror.
An angular lance of heat shot toward us. Veshra caught it but her shoulder took a grazing stripe. Black scorch marred silver scales. She exhaled through clenched teeth, mirrored shield flashing the beam upward to explode against a ceiling arch. Coolant hissed out in boiling clouds. I drew the vortex tight around the spray, herding it away from our formation. The organ under my ribs pounded, pearl flaring again, then dimming to an anemic gray.
Sweat prickled beneath my harness though water surrounded me. Vision blurred, but Yera's spear pierced the last sentinel's runes. The machine fell, limbs slack. Rejah flashed the final runic signal: charges set.
We took cover behind a support pillar. Runes pulsed, then white fire cracked the conduits. The roar felt like being inside thunder. I slammed against the pillar, fins burning from the shock. Pipes darkened. Orange light died. The conduit grid fell silent.
Water swirled with debris. As the dust cleared, I saw Exile scout Rilan bleeding from a jagged hole in her abdomen. A Shellguard pressed kelp gauze but I knew the look of mortal wounds. Rilan's eyes met mine, calm despite pain. She reached out, grabbed the Shellguard's wrist in silent thanks, then pressed a coral shard into his palm, a keepsake of peace. Water drifted from her gills one last time, and she stilled. The Shellguard bowed, tears mingling with blood in the current.
Grief swept through the squad. No Reef soldier looked at an Exile the same way after that.
A rumble rolled down the shaft, low and deliberate. Dust drifted from ceiling cracks. The water felt magnetized with tension. From a sealed tunnel, a figure appeared. Taller, broader, its armor runes etched in layered patterns. Three organs burned in its chest, their glow steady. This was no engineer, no sentinel, but a commander, its power humming against my fatigued bones.
Its visor scanned the chamber slowly, noting every broken pipe, every lifeless conduit. When it turned to me, the water itself seemed to heat a degree, runes flaring like new dawn. My hand tightened on my spear. Yera moved beside me, voice calm but iron-hard. "We cannot match brute for brute," she said. "We bleed it or we bend the water."
The commander raised one gauntlet. Runes along its forearm brightened, and heat surged through the room, rippling the water like a drumbeat. Slow, deliberate, confident. Beneath us the floor plates trembled, as if the drill shafts beyond were stirring.
The drills were silent for now, yet the way that gaze burned through me said silence was merely the pause before a deeper note. I tightened my grip, feeling the dim pearl against my ribs.