The light died on Floor 6.

  Not gradually, the way it had dimmed in the Pore Tunnels, but completely—a sudden absence that swallowed everything the moment Elias stepped through the transition membrane. He stood in absolute darkness, his eyes straining against nothing, his other senses screaming warnings that his vision couldn't confirm.

  "I can't see." Mira's voice came from somewhere to his left, tight with controlled fear. "Elias, I can't see anything."

  "Hold on."

  He reached for the Blood-Sight, calling it up the way Old Tom had taught him—not with words, but with intention, a mental flexing of the circuit threaded through his nervous system. The world transformed.

  Red light bloomed in the darkness.

  Through the Blood-Sight, the Deep Tunnels revealed themselves as a network of crimson pathways—not the tunnels themselves, but the creatures within them. He could see Mira beside him, her circulatory system blazing like a torch, every heartbeat sending pulses of brightness through her arterial network. He could see smaller signatures in the distance—vermin, maybe, or insects—scattered points of warmth in the cold dark.

  And he could see Lira, standing at his other side.

  No. He couldn't see Lira. The Blood-Sight showed only living blood, and ghosts had neither. She was a void in his enhanced vision, a daughter-shaped absence that somehow hurt more than seeing her clearly ever had.

  "Lira?" He reached out, finding nothing but cold air. "Are you there?"

  "I'm here, Daddy." Her voice came from the darkness, small and uncertain. "I can see a little bit. Not much. It's like... like looking through dirty water."

  "Stay close to my voice."

  "I will."

  He turned to Mira, who was still a beacon of red in the absolute black. "I can see enough for both of us. Take my arm. Don't let go."

  Her hand found his elbow, grip tight with the desperation of someone who'd just lost their primary sense. "How can you see? There's no light at all."

  "Blood-Sight. I can see your circulatory system, and anything else with blood in it." He began moving forward, guiding her through the darkness. "The tunnel's about ten feet wide here. Ceiling's high—maybe fifteen feet. I can see some kind of growth on the walls, but I can't tell if it's dangerous."

  "How do you know about the walls if you can only see blood?"

  "I can't. I'm inferring from the way the tunnel echoes." A skill from his military days—reading environments by sound when vision failed. "Step where I step. The floor feels stable, but I don't trust it."

  They moved through the Deep Tunnels like blind men in a labyrinth, Elias's Blood-Sight their only guide. The darkness was oppressive in a way the Pore Tunnels hadn't been—not just an absence of light, but a presence of something else, something heavy and watchful that pressed against his skin.

  FLOOR 6: THE DEEP TUNNELS

  AMBIENT THREAT LEVEL: EXTREME

  ENVIRONMENTAL HAZARD: Zero visibility (natural); predators adapted to darkness

  PRIMARY FAUNA: BILE LURKER, SHADOW LEECH

  NOTE: Sound carries. Light attracts. Blood-Sight recommended.

  "The System's recommending Blood-Sight," Elias said quietly. "Which means anyone who doesn't have it is at a serious disadvantage."

  "Most Climbers don't have circuits by Floor 6." Mira's voice was bitter. "Most Climbers are dead by Floor 6."

  "We're not most Climbers."

  They continued in silence, Elias mapping the tunnel in his mind through a combination of Blood-Sight and spatial awareness. The passage twisted and branched, forcing him to make decisions based on incomplete information—left or right, up or down, forward or back. He chose based on the concentration of small blood signatures, reasoning that vermin wouldn't congregate near major predators.

  It wasn't a perfect system. But it was what he had.

  An hour into their descent, Elias saw something that made him stop.

  Ahead, maybe fifty meters, a cluster of blood signatures moved in ways that didn't match vermin behavior. They were organized, coordinated, circling a central point with predatory patience. And at that central point—

  "There's a larger creature ahead," he said. "Something big. Can't tell exactly how big, but its blood volume is significant."

  "Threat?"

  "Unknown. But the smaller creatures are avoiding it, which suggests it's at the top of the local food chain."

  "Can we go around?"

  Elias studied the tunnel through his crimson vision. The passage narrowed ahead, funneling toward the point where the large creature waited. There might be side branches—he could see gaps in the wall where his vision terminated—but exploring them in total darkness was a gamble.

  "Maybe. But if that thing's hunting, it might have other exits covered." He made a decision. "We approach carefully. I'll try to get a better look at what we're dealing with."

  They crept forward, Elias's enhanced vision tracking every pulse of the creature's massive circulatory system. As they drew closer, details emerged—a body suspended from the ceiling, limbs splayed in waiting, a central mass that throbbed with accumulated blood.

  "It's above us," he whispered. "Hanging from the ceiling. Big—maybe the size of a car. It's got what looks like multiple appendages, and there's a large concentration of blood in what I think is its stomach."

  "Ceiling ambush predator." Mira's grip on his arm tightened. "Drops on prey passing beneath. Classic strategy."

  "If we stay against the walls—"

  "It might still reach us. Those appendages look long."

  Elias studied the creature more carefully, using the Blood-Sight to map its internal structure. The medical part of his brain kicked in automatically, identifying anatomical features through the pattern of blood flow. Heart—or hearts, plural; there seemed to be two—pumping in synchronized rhythm. Major arteries running to the appendages. And that stomach, distended with accumulated fluid, the largest concentration of blood in the entire creature.

  "I can see its weak points," he said slowly. "The stomach is overfilled—probably stores blood from previous kills. If we could rupture it..."

  "The creature would bleed out."

  "Or the shock would incapacitate it long enough for us to finish it off." He pulled away from Mira, reaching for his spear. "I'm going to try something. Stay here."

  "Elias—"

  "If this goes wrong, take Lira and run. Don't look back."

  He didn't wait for her response. He moved forward alone, Blood-Sight tracking the creature's every pulsation, counting the rhythm of its hearts, waiting for the moment between beats when its blood pressure would be lowest.

  The creature stirred.

  Even without normal vision, Elias knew it had sensed him. The blood flow in its appendages increased—preparation for movement, for the strike that would send it plummeting from the ceiling onto whatever prey had wandered beneath.

  He was counting on that.

  Three meters. Two. One.

  The creature dropped.

  It fell with surprising silence for something so large, its appendages spreading wide to engulf its prey, its body plummeting toward the exact spot where Elias had been standing half a second before.

  He wasn't there anymore.

  He'd thrown himself sideways at the moment of the creature's release, rolling across the floor as the massive body crashed down where he'd stood. The impact shook the tunnel, and suddenly the air was full of sound—a wet, gurgling shriek that cut through the darkness like a blade.

  THREAT IDENTIFIED

  CLASSIFICATION: BILE LURKER (AMBUSH PREDATOR)

  THREAT LEVEL: HIGH

  Support the author by searching for the original publication of this novel.

  NOTE: Bile Lurkers store prey's blood in stomach for later consumption. Rupturing stomach sac causes severe trauma.

  The Bile Lurker was even more horrible than Elias had imagined. Through Blood-Sight, he'd seen its circulatory system; now, through the chaos of combat, he experienced its physical reality. Appendages whipped through the air—eight of them, each ending in hooks designed to catch and hold. A body like a bloated spider, all stomach and hunger. And a mouth, somewhere in the mass, producing that awful shriek.

  "Elias!" Mira's voice, somewhere behind him.

  "Stay back!"

  The Lurker oriented on him, appendages sweeping the darkness in search of prey. It couldn't see any better than he could—it was hunting by vibration, by sound, by the displacement of air. But it knew he was close, knew he was alive, knew he was food.

  One appendage grazed his shoulder.

  The pain was immediate—those hooks were sharp, designed to grip flesh—but Elias twisted away before it could set. He brought his spear up, slashing at the retreating limb, and felt the blade bite into something that sprayed warm fluid across his face.

  Not blood. Something worse. Bile, acidic and foul, burning where it touched exposed skin.

  Vitality: 92/100

  The Lurker shrieked again, recoiling from the wound. Its movements became more frantic, more desperate—the behavior of a predator that had become prey. Elias pressed forward, using the Blood-Sight to track the creature's vital points, waiting for his opening.

  There.

  The stomach was exposed now, the Lurker having twisted to protect its wounded appendage. Through the Blood-Sight, Elias could see the massive organ pulsing with stolen blood, could see exactly where the membrane was thinnest, could see the point where a precisely placed strike would—

  He thrust the spear with every ounce of strength he possessed.

  The blade punched through the stomach wall with a wet, tearing sound, and the reaction was immediate. Blood—not the Lurker's blood, but the accumulated blood of its victims—erupted from the wound in a pressurized spray. The creature's shriek became a scream, became a howl, became a death rattle as its internal organs were flooded with digestive acids no longer contained by the stomach membrane.

  It thrashed once, twice, and then collapsed, its appendages going slack, its hearts stuttering and failing in Elias's enhanced vision.

  Silence.

  Elias stood over the corpse, breathing hard, covered in blood and bile and other fluids he didn't want to identify. His shoulder burned where the hooks had grazed him, and his skin itched where the acid had splashed, but he was alive.

  Vitality: 81/100

  HARVESTING AVAILABLE

  DECEASED TARGET: BILE LURKER (MINI-BOSS)

  ESTIMATED YIELD: 1.8 L

  He harvested quickly, efficiently, not letting himself think about the blood that wasn't entirely the creature's. When he was done, his reserves had climbed significantly—enough to feel like progress, enough to feel like the risk had been worth it.

  "That was insane." Mira's voice came from behind him, accompanied by footsteps as she approached. "You baited it. You actually baited a Bile Lurker into dropping on you."

  "I could see its internal structure. I knew where to hit it."

  "That's not—" She stopped herself, recalibrating. "Normal people can't think like that in the middle of a fight. Normal people panic."

  "I'm not normal people." He wiped blood from his face with the back of his hand. "I've been in situations where panic meant death. You learn to think clearly, or you don't survive long enough to learn anything else."

  "Where?"

  "Combat zones. Emergency rooms." He paused, the memories surfacing unbidden. "My daughter's hospital room."

  Mira didn't respond to that. Instead, she helped him clean up as best they could in the darkness, her hands finding wounds he hadn't noticed, her voice calm and practical as she assessed his injuries.

  They continued through Floor 6 and into Floor 7, the Deep Tunnels giving way to slightly wider passages that offered marginally better conditions. The darkness persisted, but Elias was learning to navigate it—trusting his Blood-Sight, trusting his other senses, trusting the instincts that had kept him alive through worse.

  They found shelter in a side chamber that showed no blood signatures for at least a hundred meters in any direction. It wasn't safety—nothing in the Tower was safety—but it was close enough for rest.

  Mira started a fire.

  Elias hadn't known she could do that—hadn't known that Tower materials could burn—but she produced something from her pack, something that ignited with a pale blue flame and provided both light and warmth without producing smoke.

  "Emergency fuel," she explained, catching his look. "Harvested from a creature on Floor 3. Burns clean, doesn't attract predators, lasts about four hours."

  "Useful."

  "I've been climbing longer than you. You pick things up."

  They sat by the fire—Elias and Mira, with Lira hovering nearby, visible now in the flame's light. The warmth was a luxury Elias hadn't realized he'd been missing, and the light was almost painful after hours of absolute darkness.

  "I had a team," Mira said.

  The words came suddenly, without preamble, as if she'd been waiting to say them and had finally found the courage.

  "When I entered the Tower," she continued, "I wasn't alone. There were five of us—people I knew from before the Bleed. Friends. Family, some of them." She stared into the blue flames, her face unreadable. "We made it to Floor 8 together. Better than most groups. We had a system, a strategy. We were careful."

  "What happened?"

  "Siphoners happened." The word came out like a curse. "They ambushed us in a transition zone. We thought we were safe—we'd just finished a fight, we were low on resources, we let our guard down." Her hands clenched into fists. "They killed two of us in the first ten seconds. Marcus and Jin. Brothers. They'd survived the Bleed together, survived getting to the Tower, survived eight floors of hell—and then some bastard with a knife opened their throats while they were still catching their breath."

  Elias listened without interrupting. He knew this kind of grief—the kind that needed to be spoken, that would poison you if you kept it inside.

  "The rest of us ran. Kara, Davis, and me. We made it to a safe zone, thought we'd lost them." Her voice cracked. "We hadn't. They tracked us somehow—blood scent, maybe, or some kind of circuit I'd never heard of. They came in the night."

  "Mira—"

  "Kara was my sister." The words were barely audible. "She was the reason I entered the Tower in the first place. She'd been taken during the Bleed, her soul dragged into this place, and I went in after her. I thought I could save her. I thought—" She broke off, her composure finally cracking. "The Siphoners didn't kill her. They took her. Alive. For harvesting."

  The fire crackled in the silence that followed.

  "I got away," Mira said finally. "Davis bought me time to run. I don't know if he's alive or dead. I don't know if Kara's alive or dead. I just ran, and I kept running, and I've been alone ever since." She looked at Elias, her eyes reflecting the blue flames. "Until you found me in that crevice."

  Elias absorbed her story, feeling the weight of it, recognizing the shape of her grief because it was so similar to his own.

  "I'm sorry," he said. It wasn't enough—words never were—but it was what he had.

  "Don't be sorry. Be useful." Mira's voice hardened, the vulnerability retreating behind walls of purpose. "You want to know why I'm following you? Because you're the first person I've met who might actually be able to help me. You've got skills, you've got a circuit, you've got a reason to keep climbing that won't let you stop. And if we keep going up, eventually we'll reach the floors where the Siphoners operate."

  "You want to find your sister."

  "I want to save my sister. Or kill the people who took her." Her jaw tightened. "Either way, I need to get stronger. And right now, you're my best chance of doing that."

  Elias nodded slowly. He understood now—her desperation, her willingness to trust a stranger, her silence when she'd first seen Lira. She wasn't just a survivor looking for safety. She was a hunter looking for prey.

  "When we find them," he said, "I'll help you."

  "Why?"

  "Because that's what I would want someone to do for me." He glanced at Lira, who was watching them with those too-blue eyes. "Because we're all looking for someone the Tower took. And because you're right—we're stronger together."

  Mira studied him for a long moment, searching for deception, for weakness, for the inevitable betrayal that the Tower taught everyone to expect. Whatever she found seemed to satisfy her.

  "Alright," she said. "Partners, then. Until the Tower separates us."

  "Until the Tower separates us."

  They shook hands, and Elias felt the compact settle into place—two broken people bound together by shared grief and mutual necessity, trying to climb out of hell one floor at a time.

  Lira drifted closer after Mira fell asleep.

  "I liked her story," she whispered. "Not the sad parts. But the part about her sister. She loves her a lot."

  "She does."

  "Do you think we'll find her? Mira's sister?"

  "I don't know, sweetheart. The Tower is big, and the people who took her are dangerous."

  "But we'll try, right?"

  "Yes. We'll try."

  Lira nodded, satisfied with this answer. She started to drift toward her usual resting position—hovering near Elias, conserving energy while he slept—but something happened.

  She flickered.

  Not the gentle dimming Elias had grown accustomed to, the natural fluctuation of her manifestation. This was different—a violent stutter, her form breaking apart and reforming, static cutting through her features like interference on an old television.

  "Daddy?" Her voice distorted, catching and skipping. "Something feels—feels wrong—"

  "Lira!" He reached for her instinctively, his hands passing through her destabilized form. "Lira, focus on my voice. Stay with me."

  She flickered again, worse this time. For one terrible moment, she was gone entirely—just empty air where his daughter had been—and Elias's heart stopped.

  Then she was back, solid enough to see, her face twisted with fear.

  "I couldn't—for a second, I couldn't feel anything. I was just... gone."

  Soul Integrity: 97.8%

  The number floated in his vision, lower than it had been after the transfusion. The stabilization was degrading, faster than expected, and he didn't have enough blood to do another transfusion without leaving himself vulnerable.

  "You're okay," he said, keeping his voice calm even as fear coiled in his chest. "It was just a glitch. The Tower's energy fluctuates sometimes. You're okay."

  "Are you sure?"

  "I'm sure." He wasn't. He wasn't sure of anything anymore. "Try to rest. Conserve your energy. We'll do another transfusion when we reach the next rest station."

  Lira nodded, dimming herself down to almost nothing, trying to minimize the energy drain. But her eyes—those too-blue eyes that saw things a child shouldn't see—stayed fixed on him until the darkness finally claimed her.

  Elias didn't sleep.

  He sat by the dying fire, watching the shadows, running calculations in his head. Blood reserves, Soul Integrity degradation rates, the distance to the next safe zone. The numbers didn't add up. They never added up.

  He was losing her, one percentage point at a time, and there was nothing he could do to stop it.

  Near dawn—or whatever passed for dawn in the Deep Tunnels—Elias heard something.

  Voices.

  They came from above, filtering down through the layers of organic material that separated Floor 7 from whatever lay beyond. At first, he thought it was another Climber party, another group making their way through the darkness. But then the pattern became clear.

  It was chanting.

  Rhythmic, synchronized, dozens of voices rising and falling in unison. The words were indistinct—distorted by distance and the acoustic properties of the Tower's flesh—but the cadence was unmistakable. This wasn't conversation. This was ritual.

  Mira woke at his touch, her eyes snapping open with combat readiness.

  "Listen," he said quietly.

  She listened. Her face went pale.

  "Siphoners," she breathed. "That's their collection chant. They do it when they're—when they're harvesting."

  The chanting continued, echoing through the tunnels, impossible to localize but impossible to ignore. It was coming from above. It was coming from the direction they needed to travel.

  "How many?" Elias asked.

  "Dozens, at least. Maybe more. They only chant like this when they've got a large group." Her voice shook with barely controlled fear—and something else, something harder. "They're close. Elias, they're really close."

  The chanting swelled, reached a crescendo, and then fell silent.

  In the darkness that followed, Elias heard something else: footsteps. Many footsteps, moving with purpose, growing louder.

  Coming down.

  "We need to move," he said. "Now."

  They gathered their supplies in seconds, moving with the efficiency of people who'd learned that hesitation meant death. Mira extinguished the fire, plunging them back into darkness. Elias activated Blood-Sight, scanning for escape routes, searching for any path that led away from those approaching footsteps.

  Above them, the chanting began again.

  Louder now.

  Closer.