Time, in the absolute dark, was measured in heartbeats.
The rat's heart. A slow, powerful thump-thump-thump that vibrated through Leo's borrowed consciousness. He lay there, a filthy barricade of fur and muscle, for what felt like hours. His mind—his human mind—slowly untangled itself from the rat's primal soup of instincts.
He learned to filter.
The overwhelming smell of the dungeon broke down into components: the wet stone, the metallic tang of old water, the sweet-rot of decaying moss, the sharp musk of his own rat-body, and beneath it all, the faint, vulnerable scent of his original insect form—a smell like clear sap and soft chitin.
He learned to control.
Moving the rat's body was no longer a desperate struggle. It was a clumsy, deliberate puppetry. He could make it stand. He could make it take a shuffling step. Its claws scraped on stone. The tail, a muscular, naked thing, lashed with a mind of its own unless he focused. He was a driver in a poorly made vehicle, but he was driving.
His original body was the priority. Through the rat's dim eyes, he watched the tiny, grub-like form. It lay still. The tear along its side had stopped leaking fluid, but it looked deflated, weak. The System's cold text hovered in his perception.
[Original Body Integrity: Critical. 22% functionality.]
It was getting worse. Not healing. Dying.
I need to fix it. How? He had no hands. No magic. Just a rat.
A new line of text pulsed softly, separate from the Symbiosis timer.
[Ambient Mana Absorption Detected. Minimal.]
[Passive healing unavailable to Parasitic Primary Form.]
[Suggestion: Direct mana conduit via active Vessel.]
Mana. So that was a thing here. The rat's body was absorbing trace amounts just by existing. Could he… use it?
He focused on the rat's body, on the faint, tingling sensation he now recognized as mana threading through its muscles and blood. He imagined pulling it, not to use, but to move. To push it out. He pictured a thread of energy flowing from the rat's core, down its leg, and out through the claw.
Nothing happened.
Frustration, a human emotion, bubbled up, causing the rat's snout to twitch and let out a low chitter. The rat's instinctual mind reacted to the frustration with agitation. It wanted to gnaw, to dig.
Wait. Dig.
Leo looked at the rat's front claws. Thick, dirty, perfect for scraping earth. He looked at his dying original body, then at the dungeon wall of packed dirt and stone beside their hideout.
An idea, fragile and desperate, formed.
He wouldn't heal his body with magic. He would protect it with engineering.
Making the rat move was one thing. Making it perform delicate, coordinated labor was another. It took dozens of attempts. The first tries sent claws gouging wildly, spraying dirt everywhere, nearly burying his insect form. He had to stop, calm the rat's instinct to just burrow frantically, and start again.
Slowly, painstakingly, he used the rat's claws like careful shovels. He excavated a small, neat niche in the wall, about the size of a human fist, deep enough to provide cover from all sides. He lined the bottom with the driest, finest dirt he could find, sifted through the rat's claws.
Then, with a precision that made his human mind ache with effort, he used the rat's snout to gently nudge his original body into the new alcove. It was a horrifyingly vulnerable feeling, moving his true self with the mouth of a beast.
Once it was settled, he used the rat's body to gather pebbles and a piece of rotted wood. He worked, chittering with effort, to fashion a crude, loose cover for the alcove's entrance—a camouflaged door.
It was a pathetic little fortress. But it was his.
[Symbiosis Stabilizing: 3%...]
[Duration to Permanent Vessel Acquisition: 166 Hours, 12 Minutes, 08 Seconds.]
The work had taken hours. But the symbiosis percentage had ticked up. Active use of the vessel strengthened the link.
Exhaustion washed over him. It was a double-layered feeling—the deep, muscular fatigue of the rat's body from unnatural, precise labor, and the mental fatigue of his own consciousness maintaining constant, stifling control.
He let the rat's body slump, its breathing heavy. He allowed some of the animal's instincts to surface—the need to rest, to conserve energy. He kept a tight leash on the hunger. The rat was starving. He could feel the hollow ache in its gut. But the thought of making it go out to hunt… the risk was too great.
Yet, he needed information. He couldn't stay in this hole forever.
Carefully, he pushed the rat's head out of their burrow entrance. The corridor was empty, silent except for the eternal drip of water. The phosphorescent moss provided a sickly green glow, painting long, dancing shadows.
He ventured out, a single step. The rat's body moved with a natural, skittering gait he now mimicked. He kept low, ears swiveling, nose constantly testing the air.
He was in a narrow, low-ceilinged tunnel. It sloped downwards. The air grew colder, damper. The signs of life were everywhere—scratches on stone, old droppings, bits of bone too small to identify.
Then, he smelled it. Something new. Something alive and different from the rat's own musk or the general decay. It was a sharp, acidic odor. He followed it, moving with a thief's caution.
The tunnel opened into a slightly larger chamber. A patch of glowing mushrooms cast a blue light over a small pool of stagnant water. And there, drinking from the pool, was another creature.
It was long and segmented, with a glossy, dark carapace. A centipede. But it was as long as the rat's body, its countless legs whispering on the stone. Its head swayed, antennae twitching.
A target.
The thought was immediate, cold, and calculative. Not from the rat's hunger, but from Leo's human mind. This creature was alone. It was likely weaker than the rat in a direct fight—its armor was tough, but the rat had weight, claws, and teeth. If he could take it… he could feed the rat's body, ending its distracting hunger. And more importantly, he could test.
Test the vessel's combat ability. Test his control under pressure.
The rat's instincts surged at the sight of prey. The simple, violent urges to attack, to bite, to kill. This time, Leo didn't suppress them entirely. He harnessed them. He let the hunger and aggression fuel the body, while his mind steered it.
He crept forward, using the shadows of the uneven floor. The centipede sensed him. It stopped drinking, its front half rising, antennae quivering violently. It let out a hiss, a dry sound like rustling leaves.
Leo charged.
The rat's body exploded into motion, a surge of fur and muscle he barely directed. He didn't try fancy maneuvers. He used the rat's natural tactic: a direct, overwhelming pounce.
He was clumsy. The charge was too straight. The centipede writhed sideways, and the rat's claws skittered off its hard side plates. A mistake. A painful, jarring mistake.
The centipede struck. Its front segments coiled and lashed out like a whip, its mandibles snapping shut on the rat's hind leg.
Pain. White-hot, shocking pain lanced through the connection. Leo felt the rat's body scream, felt its panic. The animal mind tried to flee, to roll, to do anything to escape.
HOLD! Leo commanded his own consciousness. He wrestled down the rat's flight reflex. He couldn't run. If he turned his back, the centipede would be on him.
Instead, he made the rat twist. A brutal, unnatural contortion of its spine. He ignored the agony in the hind leg and brought the rat's full weight down, pinning the centipede's middle segments with its chest. The centipede writhed, its legs scrabbling against the rat's belly.
The rat's head darted down. Leo aimed, not for the armored head, but for the softer joints between the segments at the point he was pinning.
Teeth found purchase.
The rat's jaw muscles, driven by Leo's desperate will, clamped down with crushing force.
There was a crackling, wet pop. The centipede's hiss became a shriek. It thrashed wildly. Leo held on, a grim rider in a storm of chitin and pain. He bit again, and again, tearing through the vulnerable connection.
The thrashing slowed. The hissing died. The centipede went limp.
The rat's body stood heaving over the kill, its hind leg burning with pain, blood—the centipede's acidic yellow blood and the rat's own red—mixing on the stone.
Leo felt no triumph. Only a cold, shaking relief. And a sharp, analytical assessment.
I'm bad at this. The vessel is strong, but my control is weak. I wasted the advantage of surprise. I got hurt.
He made the rat begin to feed, tearing into the soft, exposed meat of the centipede's innards. The taste was bitter, awful, but the rat's body responded with ravenous joy, and the gnawing hunger in its gut began to fade. The pain in the leg was a constant, throbbing reminder of his failure.
As the rat ate, a new System message appeared.
[Vessel sustained minor injury: Lacerated hind limb.]
[Ambient Mana Absorption facilitating natural healing. Estimated full recovery: 18 hours.]
[Active combat and consumption accelerates Symbiosis.]
[Symbiosis Stabilizing: 5%...]
[Duration to Permanent Vessel Acquisition: 165 Hours, 47 Minutes, 22 Seconds.]
Progress. Bought with pain and risk.
He finished feeding, the rat's belly now full. The leg hurt, but it could bear weight. He was turning to drag the remainder of the centipede carcass back to his burrow—a future meal—when a new sound froze him.
Not skittering. Not dripping.
Voices.
Human voices. Muffled, echoing from somewhere far above, down a connecting tunnel he hadn't noticed.
"…think the map's wrong. This branch shouldn't be this deep."
"Quit whining. The quest said moss-beetles. They like the wet zones. This is wet."
"I don't like the smell. Something died recently."
Adventurers.
Leo's insect heart, tucked away in its tiny alcove, seemed to skip a beat. The rat's body instantly crouched, melting into the shadows of the chamber. He stopped breathing, letting the rat's instincts for stillness take over.
Humans. Intelligent beings. The ultimate potential vessels, according to the System's dreadful promise. But now? They were death. A single misstep, a single glance into this chamber, and a novice adventurer could end the rat with a lucky stab. And if they found his original body…
He waited, a statue of fur and fear, as the voices grew slightly louder, argued, and then, mercifully, began to fade as they took a different passage.
The danger passed. The chamber was silent again, save for the dripping water.
Leo, inside the rat, looked at the centipede carcass. Then he looked down the tunnel where the voices had vanished.
A new hunger awoke. Not for meat. For more.
He had a vessel. He had a system. He had a crumbling insect body to protect.
And above him, in the light, walked beings of flesh and mind he was destined to infiltrate.
[Symbiosis Stabilizing: 5.1%...]
The crawl continued.