Leon didn't leave the repair shop immediately.
He crouched by the entrance, spending about ten minutes observing the street outside. Not with his eyes, but with his newly acquired mana sense. That perception was blurry—like looking through frosted glass. He could detect energy fluctuations, discern general direction and intensity, but couldn't form clear images. Still, it was already far more useful than his eyes.
In his perception, the world looked like a thermal imaging map. In the distance, several bright energy sources moved—those were wandering mutated creatures, or things that had once been human. Nearby, a faint energy source pulsed slowly, probably in hibernation, somewhere in the building across the street. His own energy fluctuation was weak, like a freshly lit oil lamp.
"Mana sense radius is about ten meters," Leon noted mentally. "Resolution is limited, but sufficient to detect close threats. Brightness probably correlates with intensity, and pulse frequency with activity level."
He added a note: "Need more data samples for calibration."
Leon took out the notebook he'd grabbed at a convenience store—he'd taken it out of habit, something to write on, and that habit had now become one of his most important tools. He opened it to the first page and began writing:
Preliminary Mana Sense Observations
1. Energy source classification: Based on brightness and pulse frequency, three preliminary categories—
· High brightness / high frequency: moving mutated creatures (presumed active)
· Medium brightness / medium frequency: stationary or slow-moving sources (presumed dormant or low activity)
· Low brightness / low frequency: self (host) and certain environmental objects
2. Energy distribution: Energy density varies across the city, strongest toward downtown, weaker at the edges. Likely related to the meteor impact point.
3. Ambient energy: A continuous background energy fluctuation in the air, frequency approximately multiples of 60Hz. This number is no coincidence—60Hz is the standard frequency of AC power. Background energy may be related to residual grid activity, or the energy wave may have coupled with the power system.
He paused as he wrote the last line. If the mana background was linked to grid frequency, that meant it could be measured with existing electronic equipment. Provided he could find working devices.
Leon closed his notebook and stood. The repair shop wasn't a place to stay long—the rolling shutter was torn, and the smell of blood (the Shadow Cat's black fluid) might attract more creatures. He needed a safer temporary shelter.
He walked to the shop's back door, pushed open the rusted iron gate, and entered a narrow alley.
The alley was flanked by high walls, with only a thin strip of sky above. The terrain made him uneasy—if threats appeared at both ends, he'd have no escape route. But his mana sense told him there were no obvious energy sources within two hundred meters ahead, and none approaching from behind the repair shop. Safe for now.
He quickened his pace, keeping his footsteps as quiet as possible. The rubber soles of his hiking boots were nearly silent on the concrete, which gave him some comfort.
After about five minutes, the alley opened into a small community park. The park had completely changed—grass grew over a meter tall, not gradually, but as if something had accelerated its growth. Several trees in the center were twisted into unnatural shapes, their trunks spiraling upward, branches extending like tentacles in all directions. A sweet, cloying smell hung in the air, like rotten fruit mixed with chemicals.
Leon didn't enter the park. He skirted around it to a three‑story brick building.
It was an old brick structure. The ground floor was a shuttered grocery store; the second and third floors looked like residences. The exterior showed no obvious structural damage, the windows were intact, and the rolling shutter was half‑open. He scanned it with his mana sense—no obvious energy sources inside.
"Potential temporary shelter," Leon judged.
He bent down and crawled under the half‑raised shutter. The grocery store was pitch‑black, shelves toppled, merchandise scattered. He used the faint light from his phone screen—battery at 43%, signal long gone, but other functions still worked.
He quickly checked the layout: front store, back storage room, and a staircase behind the storage room leading to the second floor. The storage room's iron door was intact and could be locked from inside. The storage room was stocked with various daily necessities—bottled water, canned goods, instant noodles, batteries, candles, lighters. Also several unopened five‑gallon water jugs.
"Location approved." Leon mentally gave himself a pass.
He began moving supplies.
Not randomly, but systematically. First, he cleared half the storage room, freeing about four square meters as a resting area. Then he moved the water jugs to a corner and used shelves to form a barrier. He sorted canned goods and instant noodles by expiration date—eat the soon‑to‑expire first.
This took about an hour. When he finished, he stood at the storage room door and surveyed his work.
Still not enough.
If something broke in, what could that iron door stop? Ordinary mutated creatures might be held off for a while, but something like the Shadow Cat would tear through it like paper. He needed active defense, not passive.
Leon walked into the front of the store and began searching the shelves. He found several rolls of heavy‑duty tape, a coil of copper wire, a box of iron nails, several cans of insecticide, a lighter, and a small magnetic door alarm—the cheap kind that emits a piercing sound when the two magnets separate.
He brought these back to the storage room and began assembling.
First, an early‑warning system. He attached the two magnetic contacts of the door alarm to the iron door and its frame with tape. If the door opened more than two centimeters, the alarm would sound. To increase coverage, he used the copper wire and nails to make three simple trip‑wire traps—the wire stretched about ten centimeters above the floor, one end tied to a nail, the other to a string of empty cans. If someone tripped the wire, the nail would pull free, and the cans would come crashing down.
Not high‑tech, but in this environment, any warning could buy precious reaction time.
Next, active defense. Leon looked at the insecticide cans and the lighter, his mind already calculating spray distance and flame temperature. The propellant in insecticides is propane and butane—flammable, explosive. Combined with the lighter, he could create a small flamethrower with a range of about three meters. Flame temperature around 800–1000°C, enough to injure most living things.
Of course, he didn't know if it would work on mutated creatures. But it was better than bare hands.
He taped three cans together, their nozzles aligned, and fixed the lighter in front of them. A single‑shot flamethrower—press the nozzles, ignite the lighter, and for one second it would spray three times the normal amount of flammable gas.
He tested it. The flame shot out about two and a half meters and lasted about four seconds. Good enough.
Done, Leon retreated to the far end of the storage room and sat down against the shelves. He finally allowed himself to catch his breath.
His phone showed 4:17 PM. About eight hours since the meteor fell.
He ate a can of dace with black beans, drank two cups of bottled water. The food and water helped his body recover, and his mind cleared. He took out his notebook, turned to a fresh page, and wrote at the top:
Magic Testing Plan
Then he began to write.
Not random scribbling—a complete research plan, as if he were writing an experimental protocol at MIT.
Objective: Verify whether mana can be measured, analyzed, and predicted like conventional energy.
Hypothesis: Mana is a field energy that follows specific physical laws; its behavior can be described by mathematical models.
Methods:
1. Measure mana fluctuation frequency and amplitude under different conditions.
2. Observe energy variation patterns during spellcasting.
3. Attempt to describe observed phenomena with mathematical formulas.
4. Derive new applications based on those formulas.
Equipment:
· Mana sense (innate ability)
· Notebook and pen
· Phone's voice recorder (for observation data)
· Various test materials (objects in the environment)
After writing this, Leon took a deep breath and began his first experiment.
He extended his right hand, palm up, closed his eyes, and focused on the Book of Truth in his mind. The ancient‑looking volume floated there, bathed in pale gold light, its pages rustling slightly as if waiting for his command.
"System," he thought, "display the data output of mana sense."
[Mana sense is currently a passive skill and cannot output data. Recommend unlocking [Data Visualization] function. Requires 50 KE. Current KE balance: 0.]
Leon frowned. "How do I acquire KE?"
[KE can be obtained by: analyzing unknown mana phenomena, defeating magical creatures and absorbing their mana cores, researching new spells, exploring ruins to gain knowledge, completing system tasks.]
Analyzing unknown mana phenomena. He'd done that once already—the Shadow Cat analysis had given him 50 KE, which he'd spent. So he needed to find new unknown phenomena to analyze.
Leon thought for a moment, then picked up a piece of rubble from the floor. An ordinary chunk of concrete, broken from the damaged pavement. He used his mana sense to "look" at the stone—it appeared as a dull gray, almost no energy fluctuation. But that wasn't the point.
The point was the silvery veins in his palm.
He shifted the stone to his left hand, opened his right palm, and stared at those veins flowing slowly beneath his skin. Under mana sense, those veins revealed a completely different appearance—not static patterns, but dynamic energy channels. Energy surged from deep within his body, flowed along the veins to his palm, and formed a faint energy field at his fingertips.
This was his own mana.
He was unconsciously releasing mana. Not much, but definitely releasing.
"Does this count as an unknown mana phenomenon?" Leon asked.
[Host mana release pattern detected. Current pattern: involuntary, undirected, low efficiency. Can be analyzed and optimized. Analysis requires 10 KE. KE balance insufficient.]
He needed KE. To get KE, he needed to analyze something first. But without KE, he couldn't analyze. A dead end.
Wait—the Shadow Cat analysis had given him 50 KE; that was a system‑provided "first analysis." So under certain conditions, the system offered free analysis. Perhaps there were other free actions?
"System, are there any free actions I can take now?"
[Host may perform the following free actions:]
[Basic Tutorial: Learn the core functions and operation methods of the Book of Truth.]
[Newcomer Guidance: Complete a series of simple tasks to unlock basic skills.]
[First Training Space Experience: Enter the Training Space once for free, duration 30 minutes.]
Leon chose the Basic Tutorial.
Golden text unfolded in his mind, like a textbook being flipped through rapidly. He "saw" the core mechanism of the Book of Truth—Knowledge Energy (KE) was the foundation that drove everything. Acquiring new knowledge through study, research, and practice, then converting that knowledge into KE via the Book of Truth. KE could be used to unlock new functions, upgrade existing abilities, and derive spell variants. And the process of gaining new knowledge itself also improved his understanding and control of mana.
A positive cycle: research → gain knowledge → convert to KE → unlock new abilities → more research.
"So the core is research." The corner of Leon's mouth lifted. "That I can do."
He began his second experiment.
This time, instead of relying on the system, he used his own methods. He closed his eyes and used his mana sense to feel the flow of energy inside his body. The sensation was strange—like feeling for an invisible river in the dark. Energy surged from somewhere in his chest, spreading along the silvery veins to his limbs. He tried to use his will to "guide" that energy, concentrating it at the tip of his right index finger.
At first, nothing happened. The energy followed its original path, ignoring his will.
He didn't give up. This was classic neurofeedback training—the brain needed to learn a new control pathway. He'd experienced something similar when learning guitar as a child: wanting his finger to press the right fret, the brain needed to form new neural connections. It took time, repetition, patience.
He tried again and again. Ten times. Twenty. Fifty.
On the 57th attempt, he felt it. The energy field at his right index fingertip grew stronger—so weak it was nearly imperceptible, but he felt it. He used his mana sense to verify—yes, the energy density at his index finger was about 5% higher than at his other fingers.
Success.
He opened his eyes and looked at his right index finger. At the fingertip, the air was faintly distorted, like the visual effect of heat shimmer. He touched the spot with his left hand and felt a slight warmth.
"Mana release," Leon murmured, a hint of suppressed excitement in his voice. "Directed, though not yet precise. But it's repeatable, measurable, optimizable."
He recorded the experiment process and results in his notebook, then took a photo of the fingertip air distortion with his phone—it wasn't very clear in the picture, but he was confident better equipment would come later.
After that, he began his third experiment: observing spellcasting mediums.
He had no spellcasting mediums—at least, not in the traditional sense. But he noticed that under mana sense, certain objects absorbed energy better than others. Metals, for instance. The copper wire in his hand appeared much brighter than the concrete chunk. Not because it had energy of its own, but because it conducted the ambient background energy better.
"Do materials with high electrical conductivity also have high mana conductivity?" Leon wrote the hypothesis in his notebook. "To be verified. Copper, aluminum, iron—test the mana conductivity of different metals. Also test silver and gold if available."
He looked at the shelves in the corner. There were a few stainless steel thermoses and some aluminum cookware. Good enough.
Just as he was about to start his fourth experiment, his mana sense detected an anomaly.
An energy source was approaching.
Not the wandering kind—wandering sources moved randomly, stopping and starting, with no clear direction. This one moved in a straight line at a constant speed, with a clear direction. It was heading straight for this building.
And behind it, three smaller energy sources followed.
Leon instantly went into combat mode. He turned off his phone screen, crouched behind the storage room's iron door, and peered through the gap.
Footsteps came from the front of the store. Not the quadrupedal sounds of a mutated creature—human footsteps, two feet, left and right, rhythmic. But heavier than normal human footsteps, as if carrying a heavy load.
A man appeared at the grocery store entrance.
He looked about thirty, wearing a plaid shirt and jeans, both covered in dust and dark stains. A wound ran from his forehead to his chin, already scabbed over but not infected. His eyes were bloodshot, his pupils dilated, his breathing rapid. His right hand gripped a baseball bat, his left hand held a little girl's hand.
The girl was about seven or eight, her hair messy, tear stains on her face. She clung tightly to the man's hand, her body trembling. Behind the man came a woman—presumably his wife, equally disheveled, holding an infant in her arms.
A family of four. Alive.
Leon didn't rush out. He first scanned with his mana sense—those four energy sources were indeed this family, no others. But about fifty meters behind the man, two brighter energy sources were approaching fast.
"Inside! Now!" Leon pushed open the iron door and called out in a low voice.
The man startled, raising the baseball bat. But when he saw Leon—a living person, flesh and blood, capable of speech—his expression shifted from fear to shock, then to elation.
"Someone… there's still someone…" His voice was hoarse, tearful.
"No time." Leon strode over, grabbed the man's arm, and pulled him and the girl into the storage room. "Something's chasing you. Two of them, very fast, about a minute away."
The man's face went white. "Those… those black… cat‑like things?"
"Shadow Cats. You've seen them?"
"One attacked the building we were hiding in. Several people died." The man held the girl, his voice shaking. "We escaped, but it kept chasing us…"
"One? Are you sure?" Leon frowned. He had clearly sensed two energy sources.
"O‑one…" The man's voice wavered. "Maybe… maybe two, I didn't see clearly…"
Leon had no time to pursue this. He closed the iron door and reactivated the door alarm. Then he placed the three trip‑wire traps along the path from the front door to the storage room. Finally, he gripped the tape‑bound insecticide cans and lighter, crouched by the storage room door.
"Listen to me." His voice was calm and firm, carrying an authority that compelled obedience. "I've set up warning devices. When the door opens, the alarm will sound. Also, there are three trip‑wire traps along this path that will make noise. That gives us about three to five seconds of warning."
He looked at the woman. "You, take the children and hide at the far end of the storage room, behind those shelves. No matter what you hear, don't come out."
The woman nodded, took the infant, and hid behind the shelves. The little girl followed, but the man didn't move.
"Give me a weapon." The man's voice was edged with desperate resolve. "That cat killed my friend, I want—"
"You won't be able to help." Leon cut him off, his tone not cruel but certainly not gentle. "You have no combat training, no powers, and you're already exhausted. You'll only get in the way."
The man's face flushed, but Leon was telling the truth. He could barely stand.
"Go into the storage room and guard the iron door." Leon rephrased, giving the man a task that sounded important. "If something gets past me, your job is to close that door, hold it, and buy the women and children time."
The man hesitated, then nodded and dragged his tired body into the storage room.
Leon crouched again by the storage room door, focusing on his mana sense.
The two energy sources were getting closer. Very fast, about fifteen to twenty meters per second. At that speed, they would arrive in thirty seconds.
His mind calculated. Shadow Cats were far faster and more agile than humans; he had no chance in a direct fight. But this time he wasn't in an open space being ambushed—he had a relatively confined space, early warning, traps, and a makeshift flamethrower.
He needed a plan.
Leon closed his eyes and built a 3D map of the grocery store in his mind. Front door, aisles, shelves, storage room door. He recalled the Shadow Cat's behavior from the first attack—it was fast, but its attack path was straight. It reacted quickly, but turning at high speed required space. Did it perceive prey mainly through sight? Or mana sense?
If sight, then darkness and cover were his advantages. If mana sense, he was in trouble—his energy might shine like a beacon in its perception.
Leon looked at the silvery veins in his palm.
No, his energy was faint. The Shadow Cat's energy was like a torch in his perception; his was like a candle flame. If their perception was similar, then in the Shadow Cat's perception, he might be just a small point of light, mixed in with other ambient energy sources.
That could give him some concealment.
The first Shadow Cat arrived.
He didn't see it, but he felt it. The bright energy source in his mana sense paused at the store entrance, as if observing, then slowly slipped inside. Its movement was slow, not like chasing prey, more like exploring new territory.
The second Shadow Cat didn't enter. It stopped about ten meters outside, as if on lookout.
Two, with division of labor. That meant they had basic cooperative ability—not mere beasts.
Leon's heart sank.
The first Shadow Cat moved through the front of the store. He heard soft footsteps—deliberately muffled, almost silent, but he was trained (not in combat, but the lab had many situations requiring silence) and could discern those faint sounds.
It passed the first trap.
The cans didn't fall—it had skirted around the wire. Could it not see the wire? Or did it see it so clearly that it avoided it?
It passed the second trap. Similarly avoided.
It could see the traps. Its night vision far surpassed humans, and in the dark, those copper wires and cans were probably as clear as black text on white paper.
Leon adjusted his plan. Abandon the traps, use other methods.
The first Shadow Cat was less than ten meters from the storage room door. He could feel it—in his mana sense, that energy source was blindingly bright. Its pulse frequency was faster than the previous Shadow Cat, as if in a state of high alert.
It stopped.
About five meters outside the storage room door, it stopped. What had it sensed? The scent in the air? His breathing? Or—
Leon realized something.
The man. His energy source wasn't bright in mana sense, but his scent, his heartbeat, his fear—those things the Shadow Cat could perceive without mana.
It knew people were here.
But it didn't charge. It waited. Waited for what? For the second Shadow Cat to flank from the rear?
Leon spun around. In his mana sense, the second Shadow Cat's energy source was moving—not toward the store's front door, but around the side of the building. This building had windows on the side. Though closed, glass was no obstacle for a Shadow Cat.
It was going to break in from the side.
"Everyone, get down!" Leon growled, throwing himself toward the storage room wall that faced the window.
His judgment was correct.
The glass shattered, and the second Shadow Cat burst through the window. But Leon was not where it expected—he crouched to the side of the window, not directly in front. The Shadow Cat's claws swung through empty air, smashing into a shelf and tearing a large hole in the metal.
Leon didn't waste the fraction of a second advantage. He pressed the insecticide nozzles and ignited the lighter.
Three streams of propane/butane gas ignited, producing a tongue of flame over two meters long. The fire hit the Shadow Cat's flank.
The creature shrieked, springing away and crashing into another row of shelves. Flames spread across its fur; the air filled with the stench of burning protein. But it wasn't dead—it rolled twice among the shelves, smothering the fire. A large patch of fur was burned away, revealing blackened skin underneath, but it was still standing, still moving.
And it was angrier.
Leon didn't give it a chance to counterattack. He dropped the spent insecticide cans, grabbed his fire axe, and charged.
Not straight in—he stepped on a shelf beam, leaped into the air, and swung down from above. The Shadow Cat instinctively dodged, but its burned side slowed it by a fraction. The axe blade didn't hit a vital area; it struck the creature's back, slicing through muscle but stopped by bone.
The Shadow Cat's tail lashed out like a steel whip. Leon couldn't dodge; it struck his left shoulder. Pain exploded, and his entire arm went numb. He nearly dropped the axe, but he clenched his teeth and held on with his right hand.
The Shadow Cat turned, opened its mouth, and aimed its sharp teeth at his throat.
Leon saw it. Those distorted trajectories, those wave interference patterns, those energy flow laws—clear in his perception like slow motion. He knew the teeth would reach his throat in 0.3 seconds. He knew he couldn't dodge. But he also knew that at this distance, the Shadow Cat couldn't dodge his counterattack either.
He didn't dodge.
He switched the axe to his left hand—though numb, he could still grip it—and swung, not at the creature's head or body, but into its mouth.
The axe blade sliced into the Shadow Cat's upper jaw, penetrated through the mouth, and pierced its brain.
The Shadow Cat's body went rigid, then limp. Its energy source dimmed rapidly, the light point in its chest flickering as if about to go out.
Outside, a second sound of shattering glass—not from this building, but the one next door.
The first Shadow Cat had fled. It gave up.
Leon stood in place, gasping. His left shoulder was swollen, his left arm nearly useless. His face was splattered with the Shadow Cat's black fluid, its acrid smell making his eyes sting.
But he was alive.
From the storage room came a little girl's sobs. The man's voice asked, "Is it over? Is it over?"
Leon didn't answer. He crouched, looking at the Shadow Cat's corpse at his feet. The light point still flickered, but its brightness was fading.
"Analyze," he murmured.
[Mana core detected (Shadow Cat, low‑grade). Absorb? Absorption yields 30 KE.]
"Absorb."
The light point transformed into a thin stream of light that vanished into his chest. New information flooded into his mind—not complete knowledge, but fragmented data, like memory scraps extracted from the Shadow Cat's core. He "saw" the world as the Shadow Cat saw it: a black‑and‑white view based on energy perception. He "felt" the Shadow Cat's instincts: track, hunt, devour.
And a trace of something not belonging to the Shadow Cat.
Fear. Not his fear—this Shadow Cat's fear. It was afraid of something. Not of him, but of something more powerful than itself.
[KE balance: 30.]
"Unlock Training Space," Leon said.
[Training Space·Basic unlocked. KE balance: 10. Enter now?]
"Later." Leon stood and looked toward the family in the storage room. The man held the little girl; the woman held the infant. They were all staring at him. Their eyes held fear, gratitude, and a kind of reverence bordering on awe.
"It's safe," Leon said. His voice was calm, as if announcing a successful experiment. "For now."
He began cleaning up. Righting the overturned shelves, pushing scattered merchandise aside, temporarily sealing the window the Shadow Cat had torn open with tape. The man came to help, saying nothing, silently moving things.
When they finished, Leon sat in the far corner of the storage room, leaning against the shelves, and closed his eyes.
His left shoulder throbbed badly—maybe a cracked bone. His right hand trembled, not from fear but from the physiological aftermath of an adrenaline crash. His body told him: you need rest.
But his mind wouldn't let him rest.
[Inheritor, welcome back.]
He hadn't called up this message. It had appeared in his mind automatically the moment he closed his eyes. The text wasn't the usual gold, but a deeper, almost amber light. The font style was also different—previous system messages looked like standard system fonts, but these words looked handwritten, each stroke with a unique curve.
"Welcome back." Leon repeated the words in his mind. "Back means… I've been here before?"
No answer.
"What are you? Why did you choose me?"
Still no answer.
But Leon felt it—the book, deep in his consciousness, was "watching" him in a way he couldn't understand. Not human watching, not biological watching—something more fundamental, more ancient. As if existence itself were watching him.
He didn't press further.
In this world, some questions didn't need immediate answers. Some answers would be earned with time and research.
Leon closed his eyes and began organizing all the data he'd collected today. He would systematize it, structure it, turn it into knowledge that could guide his actions.
Tomorrow, he would continue experimenting.
Tomorrow, he would continue researching.
Tomorrow, he would continue living.
And outside the storage room, in the ruins of what had once been Boston, countless energy sources roamed in the darkness, countless unknowns awaited discovery.
This was a new world.
And Leon Winchester had just begun his research.