After leaving Arthur's workshop, Lin Jie clearly recognized his significant shortcomings.

Previously, he had relied more on his 21st-century modern thinking and information processing abilities, conducting a "dimensional reduction strike" against this world where mysticism and science mingled, still in the budding stages of the industrial era.

He was accustomed to constructing tactics using "logic" and "analysis," and gauging people's hearts with "psychology" and "game theory."

These methods proved effective most of the time.

But Arthur's words bluntly illuminated his deepest predicament—when the problems he faced were constructed from a new set of rules he didn't recognize, his knowledge from the "surface world" appeared pale and powerless.

He needed to learn, to systematically start from scratch in learning and understanding this world's "underlying code."

So, carrying this craving of "must become stronger," he plunged headfirst into the central library of the Underground City.

This library was the heart and brain of the entire I.A.R.C. London branch.

Beneath a dome so high its top couldn't be seen, rows of massive bookshelves made of dark oak stood neatly arranged, extending to the limits of vision.

It housed all research reports, containment records, failure case analyses, and countless personal investigation notes exchanged for with lives by hunters over the hundreds of years since the association's founding.

It was a Babel tower concerning the "inner world," a temple of knowledge that could drive any knowledge seeker to madness.

Lin Jie lost himself here.

For the next three days and nights, he hardly left this place.

He pulled "On the Three Basic Forms and Energy Transformation Models of Spirit-type UMAs" from the shelves.

He opened another book, "Preliminary Investigation of 'Spiritual Rejection Reactions' in Grotesque Armament Forging."

He found another historical research report on the Gnostic doctrines of the "Eternal Serpent" cult.

The more he read, the heavier the anxiety in his heart grew.

The volume of information was too vast and too fragmented.

The depth and breadth of the inner world's knowledge system far exceeded his imagination.

Every branch was enough for a scholar to devote their entire life to studying.

He was like a student trying to complete all of Oxford University's courses in three days, with the only result being "indigestion" and "knowledge anxiety" from contradictory and entangled information points.

He didn't know where to start learning, much less where the focus of his studies should lie.

That obsession of "must become stronger" had instead become the mist obscuring his path forward.

On the evening of the fourth day, when Lin Jie sat at a reading table with bloodshot eyes, suffering from a splitting headache from at least seven or eight profound works spread before him from different fields like "Cryptozoology," "Applied Theology," "Runic Studies," and "Ancient Alchemy."

A voice, aged yet gentle, sounded behind him.

"It seems you're searching for a battle-axe capable of felling an entire forest, young man."

Lin Jie's body jolted.

He hadn't heard any footsteps—this voice seemed to have materialized from thin air!

He spun around sharply and saw a "person" he had never encountered before in this library.

It was a lady so elderly her specific age was indeterminable.

Her figure was small and stooped, dressed in a Victorian-era maid-style gray dress.

Her sparse silver-white hair was tied into a neat bun at the back of her head.

Her deeply wrinkled face resembled parchment that had been crumpled repeatedly.

Most impressive were her eyes.

They were gray eyes, still as an ancient well, as if they had already seen through all the partings, honors, disgraces, rises, and falls of the world.

She stood quietly behind Lin Jie.

Her presence was so faint that without careful observation, you might mistake her for a human-shaped gray shadow between the bookshelves.

This was the curator of the Underground City's central library, and its only administrator—a legendary existence known respectfully by older generation hunters aware of her as the "Gray Lady."

It was said she had no name and no family.

She had existed here since the library's very first day.

Her entire life had been devoted to these books recording countless blood, tears, and deaths.

She was the most faithful gravekeeper of this "knowledge graveyard," and one of the oldest "living histories" within the entire I.A.R.C.

"Good evening, Madam." Lin Jie immediately stood up from his chair.

Although he didn't know her identity, he could sense the unfathomable aura emanating from the elderly woman before him.

The Gray Lady didn't respond to his greeting.

She merely swept her gray eyes slowly over the chaotic assortment of books from different fields spread before Lin Jie.

Then she posed a second, equally profound question.

"Tell me, young man." Her voice was as gentle as a sigh, "Have you ever considered that sometimes, to open a locked door, what we need might not be a 'battle-axe' capable of splitting the entire door."

"But merely a key that can precisely insert into the keyhole and turn the pins...?"

This metaphorical statement struck the chaotic ocean of Lin Jie's thoughts.

He understood instantly.

These past few days, he had been trying to forge himself into an indestructible "universal battle-axe."

He attempted to master all powers, to learn all knowledge, hoping to use the most brute-force method to split open every problem he encountered.

But he had forgotten what his most core and unique "talent" truly was.

He wasn't a "warrior" nor a "craftsman."

He was an "Interpreter"!

What he needed to do wasn't to "create" power, but to "understand" power.

What he needed to become wasn't a "battle-axe," but that "key" capable of finding the vulnerabilities in the "lock" and silently opening it with minimal cost!

The Gray Lady watched the suddenly enlightened Lin Jie.

A faint smile appeared on her deeply wrinkled face.

She turned and melted back into the darkness between the bookshelves.

Lin Jie sat back down in his chair but didn't look again at the profound works from various fields before him.

Instead, from that pile, he pulled out the most basic and thinnest book—the initial sighting and containment report of the UMA he had personally participated in eliminating: the "Mist Walker."

He decided to start from understanding the life he had personally ended, step by step forging that unique key for himself.

That evening, when Lin Jie left the Underground City, exhausted but with a clear and peaceful mind, he unexpectedly encountered William, who had just finished his mission, by the flickering gas lamp at the entrance.

William invited him for a drink at a cheap public house nearby called "The Queen and Gun," frequented only by local old policemen and retired veterans.

There, the tables held no champagne or brandy, only cheap rye beer constantly foaming in pewter cups.

The patrons around weren't gentlemen and officials loudly discussing the "Empire's future," but London's lower-class people, red-faced from drinking, full of complaints from life's pressures, cursing rudely about foremen and wives.

On the walls were recruitment posters encouraging young men to join the Royal Marines and go to distant India or Africa to expand territories for the "Queen and Empire."

In the corner, a newspaper, frayed from countless oil-stained hands, featured heated front-page discussions about Prime Minister Gladstone's controversial "Irish Question."

This was the city's true underlying color.

Lin Jie and William sat in such a corner, filled with the atmosphere of daily life and its grievances.

William didn't discuss UMAs or the inner world with him.

Instead, over that bitter barley beer, using his consistently concise language, he taught Lin Jie some "surface world survival lessons" he had summarized from decades of experience navigating London's streets and alleys.

"Look at that fellow over there, dressed decently but with a layer of uniform dark red fine soil on the side of his soles." William gestured with his chin toward the bar.

"He's not a merchant;

he's a butcher. Only the land near slaughterhouses, mixed with livestock blood, would be that color."

"And that young man over there, whose accent sounds like he's from the East End docks, but insists on holding his glass with his pinky raised like the upper class." A cold glint flashed in William's eyes.

"Don't go near him. The inner side of his right index finger knuckle has a thick callus, a mark left from years of practicing with some easily concealed small knife."

"He's a thief or assassin far more dangerous than you'd imagine."

"Remember, Lin Jie, in this city, a person's 'words' are often the least trustworthy, but their 'shoes,' their 'hands,' and the 'accent' ingrained in their bones will never lie."

William, the usually silent veteran, transformed into an excellent teacher in that moment.

What he taught wasn't how to fight, but how to observe and discern, how to read the complex human codes hidden beneath the surface of this city like a true local.

Lin Jie listened with exceptional focus.

The "street wisdom" William taught him was no less valuable than the grand mystical philosophies he had gained in the library during the day.

The world he lived in was constructed precisely by these "people" before him, with their merits and flaws, kindness and cunning.

To understand "monsters," one must first understand "humans."

In the pub's slightly tipsy atmosphere, when William mentioned how he transformed from a poor country boy into this "old Londoner" who could see through everything, he inadvertently mentioned an old comrade who had profoundly influenced him.

"...The first time I came to London, I was nearly cheated out of all my demobilization pay by a swindler pretending to be a fellow villager. Frank saved me." William's tone carried nostalgia.

"Frank Harvey, an old mate who crawled out of that damned massacre with me. He understood these things better than I did, but sadly..."

"After retiring, he couldn't stand this suffocating hellhole of London. He chose a quieter, cleaner place."

"He went to... Dartmoor Wilderness to become a ranger guarding those prehistoric stones."

"Speaking of which," William furrowed his thick brows, "It's been almost half a year since I last received a letter from that fellow. I wonder how he's doing on that godforsaken wasteland."

"Ah well, I'll go check on him in a couple of days."