Chapter 36: Diminishing Returns

Kira killed the construct left-handed because her right side was a catalog of damage that wouldn't let her reach across her body for the full draw.

The knife found the throat joint—her default target, reliable across every construct variant they'd encountered—but the angle was wrong. Off by three degrees. The blade hit stone instead of the gap between plates and skidded, throwing sparks. The construct swung. Kira ducked under it, and her cracked rib screamed its objection through every nerve on her left side.

Marcus's shield caught the follow-through. His new Mark II absorbed the impact with a sound different from his old shield—higher pitch, less resonance, the acoustic signature of lighter materials and inferior metallurgy. But it held. He drove the construct back two steps, giving Kira space to reset and find the throat joint on her second attempt.

This time the knife went in clean. The construct dropped.

Floor 77 was standard combat. No adaptive enemies, no environmental twists, no hidden rules. Just constructs, waves of them, the Tower's bread-and-butter challenge testing whether a party could maintain combat effectiveness under baseline conditions.

They couldn't. Not really.

The formation was wrong because the party was wrong. Marcus had shifted to cover Kira's usual flanking position, which meant the right side of the formation was running a tank where an assassin should be. Kira fought from behind Marcus's shield—the rear guard position that David normally occupied—and her reduced mobility turned every engagement from a precision strike into a grinding exchange.

David compensated by moving forward, filling the gap Marcus had left, his lightning arcing at medium intensity in patterns that prioritized area denial over direct damage. His modified defibrillator patch sat against his chest like a second heartbeat, and every discharge carried the invisible question of whether this would be the one that stopped the first.

Maya held the center. Emma held the left. Noah directed from behind.

They cleared the floor. It took three times longer than it should have.

**[FLOOR 77 CLEARED]**

**[RANK: B- (REDUCED PARTY EFFECTIVENESS)]**

---

The rest break between floors was fifteen minutes. Noah sat against the corridor wall and ran diagnostics.

Not on the party. On himself.

The full activation on Floor 76—the one he'd used to find Kira's location in the maze—had cost something. He'd known it would. Full activations always went after the premium fuel, the memories with the highest emotional charge. The Hollowing was predictable in its cruelty.

He went looking for the damage.

The memory surfaced easily. Emma, six or seven years old, running through the sprinkler in their backyard on a July afternoon. The image was crisp—her hair plastered to her forehead, her swimsuit printed with cartoon dolphins, the fan of water catching sunlight and throwing miniature rainbows across the grass. She was laughing. He could see the shape of the laugh on her face even though he couldn't hear it (his mother had been calling from the kitchen doorway, and that audio was already gone).

Every visual detail intact. The time of day, the angle of light, the specific pattern of water droplets on Emma's skin. A photograph stored at maximum resolution.

But the feeling—

He reached for it. The joy. The specific, irreducible pleasure of watching his little sister be happy. The big-brother warmth that had no analytic component, no strategic value, no function except to exist as proof that he loved someone and their happiness was his happiness.

Gone.

Not muted. Not reduced. Gone. The memory was a museum exhibit behind glass—observable, documentable, permanently out of reach. He could describe the joy that used to live inside it the way a blind man could describe the color blue: with accuracy borrowed from a time when the information was firsthand.

He tested other Emma memories. The recent ones—climbing together, fighting together, the conversations about the Hollowing—still carried warmth. Diminished warmth, reduced from the micro-activations' cumulative erosion, but present. Detectable.

The childhood memories were emptier. The backyard sprinkler. Teaching her to ride a bike. The school play where she'd forgotten her lines and he'd whispered them from the front row. Each one hollowed to a different degree, but the trend was clear: the oldest, most emotionally dense memories of Emma were being consumed first. The foundation of their bond was being eaten from the bottom up.

At the current rate—and the rate accelerated with every full activation—his entire emotional connection to his sister was a degrading resource with a finite lifespan. Not infinite floors. Not hundreds of activations. A calculable number of full activations stood between the Noah who loved his sister and the Noah who remembered loving his sister the way he remembered the periodic table.

He looked across the corridor at Emma, who was checking Kira's stitches with careful fingers. Her hair was dirty. Her armor was scarred from seventy-seven floors of combat. She was talking while she worked—the stream-of-consciousness chatter she defaulted to when her hands were busy, half-sentences and aborted thoughts and the occasional "right?" that invited agreement nobody needed to give.

Noah watched her and tested the warmth.

It was there. He could feel it—a genuine emotional response, not a cataloged fact. The warmth was real, still real, diminished but present.

For now.

How many full activations until it wasn't? Five? Ten? Three? He couldn't calculate the exact number because the Hollowing didn't follow a linear function. It targeted the densest memories first, which meant the early losses were in the deep archive—childhood, formative experiences, the bedrock emotions that everything else was built on. But as the deep archive depleted, the Hollowing would move to more recent material. Closer memories. The climbing. The conversations. The moments they were building right now.

He made the decision in the time it took to draw a single breath.

No more full activations.

Micro-only. Regardless of circumstances. Even if someone was dying—even if Emma was dying—he would not use a full activation of Path Sight again. Because the alternative was saving her body while losing the capacity to care that he'd saved it. A rescue performed by a man who'd feel nothing about the outcome was not a rescue. It was logistics.

The decision was clean. Logical. The kind of bright-line rule his developer brain excelled at implementing.

It was also, he recognized, the decision of a person whose analytical framework had already begun to outstrip his emotional one. A person who could weigh the value of his sister's life against the value of his feelings about her life and reach a conclusion without flinching.

The fact that he hadn't flinched was the most frightening part.

Emma looked up from Kira's stitches and caught him staring. Her hands paused. She'd seen this look on him before—the assessment stare, the I'm-running-internal-diagnostics expression that had become increasingly frequent since the Memory Bloom. But something about this instance was different. His eyes had been focused on her specifically, and the focus carried a quality she could read even if he couldn't generate it on purpose.

"What?" she asked.

"Thinking."

"About?"

"Floor 78. Sera's map shows the toxic zones follow—"

"You weren't thinking about Floor 78. You were looking at me like you were trying to memorize something."

He was. He'd been committing the current image of Emma to memory with the specific intensity of a man who understood that his access to the emotional content of these moments had an expiration date. Storing the raw data while he could still pair it with the feeling. Building a backup that might survive the Hollowing's eventual advance.

"I was thinking about the formation adjustment for the toxic floor," he said. "Your speed is going to be critical for scouting between safe zones."

Emma's eyes stayed on him for three seconds longer than the conversation warranted. She didn't believe him. But Kira's stitches needed finishing, and Floor 78 wasn't going to wait, and some lies were small enough to let pass without the fight they'd require to dismantle.

She went back to work.

Noah went back to watching.

---

Floor 78 stank.

The air hit them like a physical object—thick, yellow-green, acrid enough to burn the inside of Noah's nostrils on the first breath. His eyes watered instantly. His throat constricted, the body's automatic response to an atmosphere it recognized as actively hostile.

**[FLOOR 78: THE CORROSION]**

**[OBJECTIVE: REACH THE EXIT]**

**[RULES: THE ATMOSPHERE IS TOXIC. EXPOSURE DEGRADES HEALTH AND EQUIPMENT. SAFE ZONES EXIST BUT ARE NOT MARKED.]**

"Masks," Maya said, pulling a cloth filter from her pack. Standard Tower gear—basic respiratory protection that reduced toxin intake but didn't eliminate it. "They'll buy us time. Not a solution."

Noah pulled Sera's map from his armor. The hand-drawn document was annotated in Sera's precise script—locations of safe zones marked with blue circles, toxic dead ends marked with red X's, hidden air filtration mechanisms marked with green triangles. The map covered roughly sixty percent of the floor's area, based on the Ironclads' two incomplete attempts.

"First safe zone is here." He pointed. "About two hundred meters northeast. The path Sera recommends avoids the densest toxin pockets. She notes that the left corridor branches into three dead ends, all heavily concentrated."

"How old is this data?" Marcus asked.

"One climb ago. Sera mentioned the floor's basic layout stays consistent between attempts. The toxin distribution might shift."

"Might."

"It's what we have."

They moved.

The toxic atmosphere was worse than the map suggested. Visibility dropped to under five meters within thirty seconds—the yellow-green haze thickening until the party was navigating by touch and proximity. Noah's skin itched where the toxin made contact, a crawling irritation that progressed to a dull burn over the next minute. Marcus's shield, held in front of the group as a physical barrier, developed a patina of corrosion on its surface—fine pitting that ate into the Tower-forged metal with patient chemistry.

David discharged a low-intensity arc. The lightning ionized the air in a two-meter radius, breaking down the toxic compounds into less harmful fragments. For approximately eight seconds, the air around them was breathable without masks.

"I can do that every thirty seconds," David said. "But it drains my reserves fast."

"Save it for emergencies. Masks and speed between safe zones."

They reached the first safe zone in four minutes. It was a chamber—maybe ten meters square, with a sealed door that opened at their approach and closed behind them. Inside, the air was clean. Cold. The contrast with the toxic corridor was sharp enough to make Noah's lungs ache.

"Two minutes," he said. "Rest, then we move to the second zone. Sera marks it at three hundred meters, heading south-southeast. The path crosses a section she labeled 'heavy concentration'—she lost a party member on her first attempt in that stretch."

"Lost how?" Emma asked.

"She didn't specify. Just an X with the word 'Dune' next to it. That was one of her dead teammates."

The name landed in the safe zone's clean air and nobody responded to it. Another dead climber. Another mark on a map that existed because someone hadn't made it.

They moved again.

The second stretch was worse. The "heavy concentration" zone Sera had marked wasn't just denser toxin—it was active. The yellow-green haze moved with purpose, swirling toward body heat, concentrating around anyone who stood still for more than a few seconds. The masks were useless here. The toxin saturated the cloth in under a minute.

Emma scouted. Her speed let her cross the heavy zone in bursts—twenty meters at a sprint, holding her breath, finding the next viable path and returning to guide the group. She ran five roundtrips in eight minutes, each one a held-breath sprint through air that could kill.

Maya phased in and out of the void, creating two-second pockets of clean air where the party could gasp a quick breath before the toxin flooded back in. Each phase drained her more than a combat activation. The Void wasn't meant for atmospheric manipulation. She was using a scalpel as a shovel, and it showed—her face was gray by the fourth phase, her hands shaking.

David's lightning helped, but the ionization effect was weaker in heavy concentration. Six seconds of clean air instead of eight. The math was brutal: six seconds of breathing for every thirty seconds of toxic exposure. Net oxygen balance: declining.

Marcus carried Kira.

He didn't ask. Didn't announce it. When Kira's injured leg buckled on the second sprint between phased air pockets, Marcus picked her up and put her on his shield like a stretcher, balancing her weight on one arm while the other guided the party forward. Kira's cracked rib made the deep breathing required by the thin-air safe zones an exercise in controlled agony, and the sprints between zones were beyond her current capacity.

Marcus didn't complain about the weight. Didn't slow down. His body did what it had been trained to do before the training memories were sold, and the missing Parris Island muscle memory didn't matter because some things were deeper than twelve weeks of boot camp. Some things were in the bones.

Noah tracked the group's condition with the detached efficiency that had become his operating mode. Kira: compromised, being carried. Maya: draining, four phases remaining at most. David: reserves declining, cardiac risk scaling with output. Emma: functional, running at ninety percent, only limited by oxygen deprivation. Marcus: carrying extra weight, slowing, endurance finite.

He calculated the remaining distance against the party's deterioration curve. The third safe zone was two hundred meters ahead. The exit was beyond that—another three hundred meters through what Sera's map labeled "moderate concentration." Total remaining distance: five hundred meters.

At current pace, accounting for rest stops and Maya's declining phase capacity, they had approximately eighteen minutes of viable operation left.

The distance would take twenty.

They were two minutes short.

Noah looked at Kira, being carried on Marcus's shield. The analytical mind provided a solution immediately, unprompted, with the cold precision of a compiler generating optimized code: leave Kira in the third safe zone. The party's pace increases by fifteen percent without her weight. Marcus's endurance extends. They reach the exit with time to spare. Return for Kira afterward.

The solution was efficient. It was also cruel.

He looked at the numbers again. Kira, injured and oxygen-deprived, alone in a safe zone on a floor designed to kill. The rest of the party, two minutes faster, able to reach the exit and come back.

The math worked. The math always worked. The math had no opinion about a woman who'd said *thank you* for the first time in years because someone sat beside her while she bled.

Noah dismissed the thought. Not with the moral revulsion that should have accompanied the idea of abandoning an injured party member—that response was behind glass now, observable but muted. He dismissed it because the tactical risk of splitting the party again, after Floor 76, was higher than the two-minute time deficit.

But the thought had existed. Had formed in his mind fully structured, complete with justification and counter-arguments, before he'd chosen to reject it. The Hollowing hadn't created the thought. His developer brain had. The Hollowing had just removed the emotional circuit breaker that would have killed it before it fully formed.

"We stay together," he said aloud. Nobody had asked.

"Obviously," Emma said, and the word carried the specific emphasis of someone who couldn't imagine the alternative and would be horrified to learn it had been considered.

---

They made it by improvising.

The third safe zone gave them four minutes of recovery. In those four minutes, David studied the air filtration mechanism Sera had marked with a green triangle—a device embedded in the wall that sucked toxin out of a small area and converted it to inert gas.

"I can overcharge it," David said. "Push lightning into the filtration system and expand its radius. Instead of this room, it covers maybe... thirty meters of corridor."

"For how long?"

"Until the mechanism burns out. Which will be fast. Maybe two minutes."

"Two minutes at thirty meters is sixty meters of clean air."

"If I push it. Full output." David's hand went to his chest. To the patch. "It's a risk."

"How much of a risk?"

"The patch catches arrhythmia at onset now. Sub-second response. Pell's modification. But full output into a foreign system, with the power routed through the mechanism instead of an enemy..." He shrugged. "Unknown variable. Could be fine. Could be the three percent that isn't."

Marcus shifted Kira's weight on his shield arm. Maya leaned against the wall, her face still gray, her phase capacity depleted. Emma stood by the door, breathing the clean air like it was the last she'd ever taste.

"Do it," Noah said.

David put his hands on the filtration mechanism and unleashed everything.

The effect was immediate and spectacular. Lightning flooded the device, overcharged its capacity by an order of magnitude, and the mechanism roared to life with a sound like a turbine engine clearing its throat. Toxic air in the corridor beyond the safe zone started moving—pulled toward the mechanism, filtered, converted, expelled as clean oxygen in a rolling wave that expanded outward from the chamber.

Twenty meters of clean air. Thirty. The wave kept pushing.

"GO!" David shouted, and the word cost him—his hands were locked onto the mechanism, his body a conduit between his own ability and the Tower's infrastructure, and he couldn't let go without collapsing the effect.

They ran. Marcus with Kira on his shield. Maya stumbling, empty, running on will instead of ability. Emma at the front, clearing the way. Noah beside David, watching the Lightning Mage's face for the specific grimace that would mean the patch was activating.

The clean air held for ninety seconds. They covered two hundred and fifty meters. The mechanism burned out with a sound like a transformer blowing, and toxic air flooded back into the corridor in a yellow-green wave that caught them in the last hundred meters.

Fifty seconds of held breath. The exit portal glowed through the haze like a distant star.

They reached it. Stumbled through. Collapsed on the other side in a heap of corrosion-scarred armor and burning lungs and the specific, gasping relief of people who'd just outrun an atmosphere that wanted them dead.

David's hand was on his chest. One second. Two. He pulled his hand away. Flexed his fingers. Looked at Noah and shook his head.

Not this time.

**[FLOOR 78 CLEARED]**

**[RANK: A- (CREATIVE USE OF FLOOR MECHANICS, FULL PARTY SURVIVAL)]**

---

The safe corridor before Floor 79 was long and well-lit, a deliberate decompression zone the Tower provided before the final push to Floor 80's boss. They had time. Time to repair gear, treat Kira's wounds, let Maya recover her void capacity, let David's reserves rebuild.

Time to talk.

Emma found Noah at the corridor's far end, sitting with his back against the wall, staring at the ceiling with the blank expression she'd learned to read as internal processing rather than vacancy.

She sat beside him. Not close. Not touching. A deliberate gap of fifteen centimeters that said: *I'm here but I'm not going to pretend this is casual.*

"On Floor 76," she said. "You used a full activation to find Kira."

"Yes."

"You told me after Floor 67 that the full activations are worse. That they target the strongest emotions first."

"Yes."

"On Floor 77, you were staring at me. Not the quick-check stares. The long ones. The ones where you look like you're running a search query on your own brain."

"That's an uncomfortably accurate description."

"What did it take, Noah?"

The question was direct. Emma didn't soften it, didn't frame it as concern or couch it in gentler language. She asked the way a surgeon asks a patient where it hurts—not to be cruel but because the information is necessary and indirection wastes time that neither of them has.

Noah looked at his sister. Tested the warmth. Found it—present, diminished, real. He could still feel it when he looked at her now, in this moment, on this floor. The warmth was threadbare in places, thin as old cloth, but it was there.

The childhood memories were another story. The sprinkler. The bike. The school play. All hollowed. All stripped of the specific joy that had made them important enough for the Hollowing to target.

He could tell her the truth. Could say: *It took the feeling of loving you when you were small. I can still see you running through the sprinkler but it doesn't make me happy anymore. I remember teaching you to ride a bike and it's a documentary, not a home movie. The deep archive is going, Emma. The foundation. And if I use full activations again, the recent stuff goes next.*

He could say that. She deserved to hear it.

But saying it would break something in his sister that the Tower couldn't repair. The knowledge that her brother looked at their shared childhood and felt nothing—that was a wound no Bond Heart could heal.

Emma waited. Her jaw was set. Her eyes were steady. She'd braced for the answer the way she braced for a blow—feet planted, center of gravity low, ready to absorb whatever landed.

"You," Noah said. "It took you."