The voices faded, leaving only the echo of their passing in Leo's mind.
He waited in the rat's body for a long time, a statue of matted fur and pain. The ache in its hind leg was a dull, persistent throb, a timer counting down to the moment he might need to run or fight again. The adventurers were gone, but their presence had changed the dungeon.
It was no longer just a habitat of monsters and decay. It was a place visited by people. People with light, with tools, with purpose. And to them, his rat vessel was just another monster to be put down for a few copper coins.
The risk calculus had just become infinitely more complex.
With careful, silent movements, he dragged the remainder of the centipede carcass back to his burrow. The effort sent fresh jolts of pain through the rat's leg. He shoved the meat into a side alcove—a larder. Then, he collapsed the rat's body at the entrance once more, a weary sentinel.
His attention turned inward, to the System.
[Original Body Integrity: Critical. 21% functionality.]
It was still declining. Slowly, but surely. His true form was starving to death, unable to feed, unable to move. The rat's body was sustained, but it was just a shell. A tool. If the original body died, what happened to him? Would he be trapped forever in the rat? Would he die with it? The System gave no answers.
He focused on the earlier message. Direct mana conduit via active Vessel.
He had failed to push mana out before. But what about pulling it in? Not for the rat, but through the rat.
He turned the rat's head, gazing at the faintly glowing moss nearby. It held trace mana. The centipede's body likely did too. The very air, according to the System, held ambient energy.
He focused on the rat's body, on the faint tingling of absorbed mana within it. He imagined that energy not staying, but being channeled. A pipe. A wire. He visualized it flowing from the rat's core, not to its limbs, but out along the invisible thread that connected him to his original form.
He pushed his will against the connection. For minutes, nothing happened. Then, he felt a subtle shift. A trickle. Not of substance, but of sensation—a cool, faint stream flowing from the rat's reservoir, down the psychic tether, into the dying insect in the alcove.
[Mana Conduit Established. Efficiency: 0.8%.]
[Original Body Integrity: Critical. 21% functionality.]
It wasn't healing. But the decline had stopped. The number held at 21%.
A wave of profound, quiet relief washed through him. It wasn't a victory. It was a stalemate. But in his position, a stalemate was a miracle. He could sustain his true body. He just had to keep the rat alive and connected.
This changed everything. Survival was no longer a frantic, hour-to-hour scramble. It was a project. A grim, dark project with a single, stark requirement: maintain the vessel.
The rat's leg needed to heal. That required rest and mana. He settled in, allowing the rat to lapse into a shallow, animal sleep while his own consciousness maintained the thin, steady drip of mana to his original form. He was a caretaker and a prisoner in a single, filthy body.
Hours passed in the deep dark. The Symbiosis percentage ticked up slowly.
[Symbiosis Stabilizing: 7%...]
When the rat's body awoke, the pain in its leg had receded to a stiff ache. It could put full weight on it. The dungeon's innate mana and the creature's own vitality were doing their work.
It was time to scout. Not to fight, not yet. To learn. He needed a map. He needed to understand the traffic patterns—of monsters, and now, of adventurers.
He ventured out again, moving with more confidence but no less caution. He avoided the chamber where he'd fought the centipede, taking a different, narrower fork that sloped upwards. The air grew slightly less damp. The stone here was worked in places—rough, ancient tool marks. He was in an old, collapsed section of something that might have once been a structure.
He found bones. Not small creature bones, but larger, thicker ones. A ribcage too big for a human, fused together by mineral deposits. A skull with long, blunt teeth. Some long-dead dungeon beast.
And then, he found something else.
A shimmer. A faint, almost invisible distortion in the air at the end of a short, dead-end passage. It looked like heat haze, but the air was cold. The rat's nose twitched. No unusual smell. Its ears picked up no sound.
But its instincts screamed. Danger. Wrong. Leave.
Leo pushed the rat a step closer, curiosity overriding the animal's fear. He picked up a small pebble with the rat's mouth and, with an awkward flick of its head, tossed it towards the shimmer.
The pebble passed through the distortion.
And vanished.
Not with a sound. Not with a flash. It was just gone. A moment later, there was a soft plink as a perfectly clean, slightly smaller pebble dropped from the bottom of the shimmering patch onto the floor.
It had been dissolved. Eaten.
A Gelatinous Cube. Or some dungeon equivalent. A transparent, acidic ooze that filled corridors, digesting anything that wandered into it. A perfect, silent trap.
His mind, the calculative part, immediately began working. A natural hazard. Deadly to anything that touched it. But also… a defense. A barrier. If he knew where it was, he could use it. Lure threats into it.
He backed the rat away carefully, marking the location in his mental map. This was valuable intelligence.
His exploration continued, revealing a network of tunnels on this upper sub-level. He found a stream of foul, slow-moving water—a water source, albeit a risky one. He found nests of giant beetles, which he gave a wide berth. He found another rat colony, and his vessel's instincts thrummed with a mix of territorial aggression and pack recognition. He steered clear. A fight with multiple rats was a fight he'd lose.
He was returning to his burrow, his mind cataloging resources (water, the centipede larder, the cube trap) and threats (beetles, other rats, adventurers), when a new scent caught the rat's attention.
Blood. Fresh blood. And the smell of iron and leather.
He followed it, creeping to the edge of a wider tunnel. The scene was clear in the moss-light.
A human adventurer lay slumped against the wall. A young man, maybe in his late teens, with cheap leather armor stained dark red across the torso. One hand clutched a broken short sword. The other was pressed against a gruesome wound in his stomach, trying vainly to hold in his insides. His breathing was a wet, ragged gasp. His eyes were wide with shock and terror, staring at nothing.
A few feet away lay the source of the damage: a large, furry spider with legs snapped, its body pierced by the broken sword. A mutual kill.
The adventurer was alone. His party was nowhere in sight. Perhaps they'd fled. Perhaps they'd gotten separated. It didn't matter.
He was dying. Alone in the dark.
Leo watched from the shadows, the rat's heart pounding against his own cool scrutiny. Here was a vessel. Infinitely superior to a rat. A human body. Hands. A voice. A mind that could think, plan, blend in.
The System's promise whispered in his soul. Invade. Control. Rewrite.
The dying boy was the perfect opportunity. Weak. Defenseless. His mind would be easy to overwhelm.
The rat's body tensed, ready to move forward, to get close enough for Leo to launch his consciousness-thread.
But he stopped.
He looked at the wound. The massive trauma. The blood loss. Even if he took over, how long would that body last? Minutes? An hour? The System said host destruction while linked was fatal. If he jumped in and the body died before he could jump out, he died with it.
Furthermore, the boy's party might return. They would find their friend, perhaps still alive, acting strangely. Or they would find his corpse. Would they notice something wrong? Would a priest detect a parasitic presence?
The risk was immense. It was a gamble with his very existence.
Then, the boy coughed, a spray of blood dotting his chin. His glazed eyes seemed to look straight into the shadows where the rat hid. A pathetic, desperate sound escaped his lips. "H… help…"
It was a human voice. Full of pain and fear. A sound Leo himself had been incapable of making since waking in this hell.
A cold, hard certainty settled in Leo's mind.
This was not the vessel. Not like this.
He was a parasite. A predator. But he was not a reckless one. Taking a vessel on the brink of death was stupid. Taking a vessel that would immediately attract attention was stupider.
He needed a vessel that was healthy. Stable. And whose disappearance or change would not be questioned.
The boy's breathing grew shallower. The plea for help faded into a soft, final sigh. The light left his eyes.
Leo watched him die. He felt no sorrow. No pity. Only a sharp, clinical assessment. A resource had expired before it could be safely utilized.
He waited a long time. Then, he scurried forward. Not to the body, but to the broken short sword. He nudged it with the rat's nose. The hilt was intact. The blade was sharp for a few inches before it snapped.
A tool.
With great effort, he managed to grip the leather-wrapped hilt in the rat's teeth. It was awkward and heavy, but he could drag it. He pulled it away from the corpse, back towards his burrow. A weapon. Crude, but better than claws against some threats.
He left the body and the spider. Let other dungeon scavengers deal with them. He had what he needed.
Back in the safety of his burrow, he dropped the sword hilt and resumed his position, the mana trickle to his original body never having stopped.
He looked at the rat's claws, then at the stolen sword hilt.
He had defended his hiding place. He had mapped hazards. He had acquired a tool. He had witnessed death and made a strategic choice.
He was not just surviving anymore.
He was building.
[Symbiosis Stabilizing: 9%...]
[Duration to Permanent Vessel Acquisition: 161 Hours, 11 Minutes, 44 Seconds.]
The original body' integrity held at 21%.
The crawl was becoming a deliberate, patient advance.