The rat behind the clinic was not a rat.
Slagfall used the word for anything that nested in the warm ducts and stole heat from the walls. This one was a rift-tick the size of Ren's boot: dull gray chitin, six legs, a mouth like a rusted staple driven into living meat. Rift-ticks were printed things. When a small tear opened in the waste and the watch was slow with the anchors, ticks came through with the rest of the small print and followed warmth. They entered the settlement when the pulse-posts flickered.
The pulse-posts were the fence's true teeth. Each post was a steel spine set in concrete, taller than a man, with a Grade Two crystal seated in a shielded cradle behind a dark window. The stone took a charge from the district grid and spent it as a low, constant push that most printed beasts would not cross. Grade Two was the Compact's ordinary work-stone. It held a pattern well enough for a sidearm, a clinic scanner, or a fence. It did not forgive a cracked seat. When a post flickered, the lattice inside had either cooled wrong after a repair or taken a residual hit from a tear that opened too close. Insulation in the stacks smelled like burnt hair after a tick had been at it, because ticks ate the wrapping off the lines and left the copper bare.
Cinder's entire body went still on his shoulder.
[There. Warm. Wrong-warm. Small enough.]
The overlay woke without being asked.
HUNT FLAG: ACTIVE
TARGET: RIFT-TICK (JUVENILE)
THREAT TO HOST HABITAT: MODERATE
SUGGESTED APPROACH: FLANK / SPARK / PIN
SYNC REQUIRED: 25%+
CURRENT SYNC: 22%
Twenty-two was short of the suggestion. The matrix offered the hunt anyway. Ren crouched by the clinic's rear grate. Afternoon heat made the metal tick in a different way than a pulse-post ticked: expansion, not charge. The alley was empty. Gray-status youth were supposed to stay where a watch camera could find them and do nothing a report would have to name. This was neither.
"You said tactics."
Cinder slid down his arm and landed without a sound. For a creature that had been an egg the day before, she moved as if she had done this a hundred times in a life she had not yet lived. The bronze plates along her shoulders tightened. The two pairs of wings opened a finger's width and held there, not for flight, for balance.
[You are tall. Tall blocks the hole. I am magnificent and low. I go in. You do not let it run up your pant.]
"That is the whole plan."
[The plan is I bite, you do not scream, we both become less small.]
The link carried more than jokes. When she looked at the grate he felt the draft on his own face, though his eyes were higher than hers. He felt the heat-line of the tick's body as a wrong warmth, distinct from the grate and distinct from the stove-heat he already knew. He felt the exact gap in the chitin behind the second pair of legs, the place a spark would matter. Shared proprioception. The matrix had named it in clean type. Living it was less clean. It was a second set of nerves that did not belong to him and did not wait for permission.
He put his palm on the grate and lifted.
The tick bolted.
Cinder was already moving.
The spark was not a fireball and not a rifle pulse. A rifle pulse was a seated crystal spending a stored pattern down a barrel in a line the smith had taught it. This was a spit of white-blue no longer than a finger, ugly and precise, generated in Cinder's throat and thrown along the channel the matrix had begun to carve through Ren's attention. He did not cast it. He aimed it the way a man aims a hose he does not own. The spark hit the tick in the joint she had shown him. Chitin cracked with a sound like a cheap lamp-housing splitting. The tick shrieked in a register that made the fillings in Ren's teeth ache.
SPARK OUTPUT: 0.7 kJ
CONTROL: POOR
SYNC: 22% → 27%
NEW: PIN REFLEX (PARTNER-LED)
Seven-tenths of a kilojoule. Still less than a healthy Grade One lamp core stored for a night's light. Spent in a speck, it was enough to break a juvenile joint. Control: poor. The spark had gone where Cinder wanted it and where Ren had looked. If those two places had disagreed, he did not know which would have won.
Cinder hit the tick from the side, jaws on the neck-plate, all four wings flared so she would not roll. Ren did the tall part. His boot came down on the thrashing tail and pinned it to the grit so the body could not corkscrew back into the duct and take its shriek into the walls.
Four seconds. It felt like a minute. The pin reflex was hers and then it was his, a borrowed order in the muscles of his leg: hold, do not ease, wait for the thrash to finish. When the tick stopped moving, Cinder sat on the corpse as if it were a hill she had been given and licked a smear of ichor off her own nose.
[See. Tactics.]
Ren's hands were shaking. Not fear. The link was still open, and Cinder's satisfaction poured through it—hot, bright, we did that. His pulse had matched hers without asking. Twenty-seven percent. The join had taken the kill as proof and written a higher number.
He crouched and looked at the body the way his father had looked at a seized pump: what broke, what could be used, what would ruin a tool if you put it where it did not belong.
The overlay obliged.
SALVAGE
— Rift-chitin (low grade): 2 shards
— Residual charge: trace
BOND NOTE: First cooperative kill registered.
MATRIX STABILITY: +3%
CLASS FIELD: STILL EMPTY
HINT: Host is not a Caster. Host is not a Knight.
Host is an interface.
Rift-chitin was not crystal. Crystal had a lattice that could be seated in steel or polymer and taught to hold a pattern. Chitin was printed armor, useful as scrap plate or as a warning that more ticks would follow the smell if you left the body in an alley. Low grade, the overlay said, the same way a foreman said low grade about a dirty seam of Grade One stone: not worthless, not worth a foundry's time. The residual charge was a faint sting when Ren's knuckle brushed a shard, like the leftover bite in a cracked lamp core. Trace. Not enough to light a strip. Enough to tell him the tick had been carrying a scrap of the tear that made it.
Interface.
Ren sat back on his heels in the alley grit. The word sat in his head the way a tool sat in a hand—wrong if he treated it like a hammer, right if he treated it like a coupler. A Caster would have lifted the grate without touching it. A Knight would have put a boot through the tick and not needed a spark. An Artificer would have looked at the chitin and the charge and started measuring a cradle. A Field Medic would have been elsewhere, closing a wound. The Key had given him none of those. The matrix had given him a channel.
Cinder was not a pet. She was not a licensed familiar with a breed-book and a feeding chart. She was the other half of a circuit the Compact templates did not have a drawer for.
"I am the socket," he said aloud, testing the shape of it. "You are the current."
Cinder considered this with the gravity of a creature who had existed for one day.
[You are also the dumpster-finder and the tall blocker. Do not reduce yourself to hardware. Hardware does not share the good warm.]
She butted his wrist. The three marks at his throat warmed in answer, a dull coal-glow under the skin. When he focused on them the overlay expanded, not as poetry, as a partial schematic the precursor architecture was willing to show.
BOND MATRIX — PARTIAL SCHEMATIC
[HOST] ──sync── [CINDER]
│
└─ growth coupled
host physical: +trace (reflex, heat tolerance)
partner mass: +0.3 kg since hatch
next threshold: 35% sync
WARNING: Rapid sync without rest may invert.
Inversion: partner feeds on host vitality.
Do not skip meals. Do not skip sleep.
Coupled growth meant the join did not raise only one side. She had taken mass since the egg. He had taken a half-step in reflex and a dullness to heat on the side of his neck where she rode. Trace changes. The next threshold sat at thirty-five percent. Inversion sat under that number like a cracked seat under a rifle stone: ignore the cooling rate and the piece does not merely fail, it turns on the hand.
Helpful. Also unnerving.
Ren wrapped the tick in a scrap of tarp. Pit habit. Rift-meat left in an alley called the next print the way blood called a second tick. He carried the bundle to the incinerator chute behind the parts depot and fed it to the heat. The chute's igniter ran on a Grade One core in a blackened housing, the cheapest stone that would still throw fire on command. The core looked tired. Someone would reseat it before the week was out or the chute would start needing two pulls. He washed his hands in the solvent sink until the iron-ozone smell faded from his skin and did not fade from the memory of the link.
Cinder rode his shoulder the whole way, heavier than she had been that morning. Not much. Enough to notice. Three-tenths of a kilogram was a small number until it was living plate hooked into a patched seam.
[We grew.]
"You grew. I received a headache and a lecture from a menu."
[The menu is also mine. I like that it agrees I am magnificent.]
Mara was home early. Second shift had cut for a conveyor jam in the lithium cut, the kind of jam that meant a belt-crystal had crazed and the whole line had to stop before the belt cooked itself. Grade One belt-seats failed that way when a foreman stretched a core past its service hours. She took in the chitin dust on Ren's boots, the brighter bronze of Cinder's plates, and the faint three marks at his throat that the collar had not quite hidden.
"Are you going to tell me what the second scan said, or do I wait for a Compact flyer on the door?"
"Gray file." He set the chit on the table. "Not Null. Not Elite. They do not have a name. Seventy-two hours, then another look. I stay in the settlement."
Mara read the stamp the way she read a work order: first the restriction, then the date, then the name that would be blamed if the restriction was broken. Then she looked at Cinder, who was attempting to look like a heater and failing because heaters did not steal grain from the pot.
"And that?"
"Cinder. She is connected. I can hear her. There is a system. Like a haul-reader that lives behind my eyes and only works when she is close."
He expected fear. He received a long silence and then his mother's practical nod, the same nod she used when a pump was going to fail in three days and the block planned around the failure instead of pretending the pump would repent.
"Then you eat. Both of you. And you do not go looking for bigger things than ticks until you know what happens if that percentage jumps too far." She tapped the chit. "Undefined is not the same as safe."
Cinder projected, very clearly, an image of Ren eating an entire second bowl.
[She is correct. Growing requires fuel. I will supervise.]
Ren ate. The food tasted the same as yesterday. His body did not. Reflexes sat a half-step closer to the surface, as if the time between seeing a motion and moving toward it had been trimmed. The heat from the stove did not bother the side of his neck where Cinder had been parked. Small changes. Coupled growth. The matrix had not lied.
After, he sat on his bunk with the door closed and pulled the overlay open on purpose. Focusing on it was getting easier. That, too, was a kind of growth, and he did not know whether to trust it.
HOST: REN CALDER
STATUS: GRAY / OBSERVATION
CLASS: —
KNOWN FUNCTIONS
1. Link-speech
2. Shared sense (hunt / heat / proximity)
3. Spark channel (partner-generated, host-aimed)
4. Coupled growth (slow) LOCKED — Named Class — Formal skills — Off-settlement travel NEXT SCAN: 61 hours OPTIONAL DIRECTIVE Understand the matrix before the specialist names it for you.
He let the text sit until the letters stopped feeling like someone else's property. Spark channel: she generated, he aimed. Shared sense: hunt, heat, proximity. Coupled growth: slow, if he slept and ate. Locked: everything the Compact would have recognized as a life.
Cinder curled against his ribs, already half-asleep, tail hooked around his wrist so the circuit would not break. The second pulse settled under his own and kept time.
[Tomorrow we find a bigger grate. Not too big. We are still becoming.]
"Tomorrow we do not get fined for hunting in an alley."
[Compromise: a grate that no one is looking at.]
The weak phase was still on him. No crest. No stipend. No clean Compact word for what he was. The empty line that said CLASS: — felt less like a verdict than like a space. Interface. Socket. Bondwright, if a specialist ever came down from orbit and needed a real word, or if Ren filled the line himself before anyone else was allowed to.
Until then: ticks, sync, food, sleep, and a sparkdrake who thought tactics meant do not let it run up the pant.
He could work with that.
SYNC: 29%
REST CYCLE RECOMMENDED
PARTNER: ALREADY COMPLYING