Hello, is this a letter addressed to Demon Fortress?

the other side.

Lin Gui did not rush back to the post office.

After leaving the old bookstore, he returned to the Elemental Heart Library and began to complete the final piece of the Illusionary Landscape spell with the Astigmatism spell he had acquired.

The reason I didn't go back to the post office was because it was being monitored.

Even though Lin Gui eliminated all surveillance methods within the post office, he still couldn't prevent external spying.

The most direct manifestation of this is the letters Elvia has received in the past few days.

Of the more than 1,000 letters sent from Greenwood Court and White Poplar Castle to Thousand Towers, the receipt rate has now reached 60%.

Due to the vastness of the Thousand Pagodas region, different identities are required to enter different areas.

Most of the letters from these two city-states were sent to the magic academy, as well as other places that were scattered around.

Therefore, progress has been relatively slow.

Receiving new emails, however, is much smoother.

In just one week, Elvia said she received 2078 letters.

However, Lin Gui's system notification showed that only 1562 emails had been received.

Lin Gui had encountered this situation before.

The system's explanation is as follows.

Of all the letters I received, some were fake; there were no recipients, they were all fabricated.

The reason Lin Gui received such letters in the past was because of Elvia.

Elvia's beauty led many to try to catch a glimpse of her under the guise of delivering letters.

Seven copper coins weren't much money for most people.

But there won't be many people like that.

Because Elvia herself possesses an aristocratic aura.

They only restrained themselves a little when Lin Gui was around.

When he's not around...

They consciously deposited their letters into the corresponding boxes and completed the registration themselves.

What's a signboard girl?

That is the ancestor who bestowed favors.

This action, this attitude.

In addition, there was an air that revealed her noble status.

Many customers who came because of her reputation eventually left the post office in fear.

Nobles... to the lower classes, no matter how beautiful they are, are walking scourges.

They might kill someone just because they don't like them.

This is all too common at the grassroots level.

Therefore, although there were invalid letters in the past, there weren't many.

Even at Green Shade Court, where the guests are all from middle-class cities, only a dozen or so out of a thousand letters are invalid.

And Qianta received a full half thousand invalid letters.

It was practically telling Lin Gui that a large number of spies had infiltrated the post office's customer base.

As the core of stealing the Mountain-Breaking Dragon, he needs to test the magic after completing the final piece of the puzzle.

This must not be seen by anyone.

Therefore, the library in the Heart of Elements is an excellent choice.

Nobody knows he's here.

After returning to the library, Lin Gui went to a very secluded place on the top floor where no one went.

It was a small cubicle hidden by bookshelves, almost against the wall, with only enough room for one person to squeeze through sideways.

The surrounding area was piled with dusty old periodicals and yellowed outdated textbooks, as if no one had touched them for many years.

He first checked his surroundings to make sure there were no listening runes or alchemical creatures.

Then he took out several small rune stones from his storage space.

Arrange the bookshelves along the entrance of the cubicle and the edges of the bookshelves on both sides.

Each runestone is activated with magic, forming a weak force field network among themselves.

Anyone who steps into this area.

The runestone would then emit a silent vibration, alerting him via a sub-runestone that had been placed in his pocket beforehand.

The second layer consisted of several extremely fine spider silk threads that he had laid on the ground and at the corner of the table.

This spider silk was used by dwarven alchemists to capture intruders.

It is colorless and odorless, almost invisible to the naked eye, and will break silently once touched.

If it breaks, another miniature alarm he set up will be triggered.

After doing all this, he took a bunch of tools out of the storage space.

A folding table, a chair, a few magic stone lamps, and a thick stack of parchment and ink.

He arranged them one by one, then took out the original scroll of the Illusory Landscape Technique that he had repeatedly revised from his pocket and spread it out on the table.

The edges of the scroll were frayed, and the paper was covered with layers of dense runes and annotations.

Some parts were crossed out seven or eight times and then rewritten.

Lin Gui unfolded the scroll of the Astigmatism Technique in front of him.

His gaze slowly moved along the runes and circuit diagrams.

The difference between the official version and the stripped-down version was now clearly displayed before his eyes.

Those deleted nodes are like missing puzzle pieces, preventing the entire magic from functioning completely.

When he filled in these nodes according to the markings on the orthodox scroll, the entire magical structure immediately changed.

Lin Gui closed his eyes and mentally simulated the entire astigmatism spell construction loop.

Every connection between nodes and the flow of every stream of magic unfolded clearly in his inner vision.

He opened his eyes.

Then I began to integrate Astigmatism into the framework of the Illusionary Realm spell.

It's like embedding the last brick into the top of an arch.

The entire structure resonated with an invisible force at that moment.

Those stuck areas began to loosen, flow, and recombine.

The originally flawed Illusionary Spell became flawless after being filled in by the Complete Astigmatism Spell.

In fact, Lin Gui himself is capable of deriving the complete version of the Astigmatism Technique from the censored version.

Just as he told Lillian, the construction loop for basic magic is very simple, not to mention there is a stripped-down version that provides construction ideas.

The problem is that the missing loops are enough for Lin Gui to spend at least two months deriving.

He doesn't have the time to do that.

Now, all of that has been resolved.

In the following days, Lin Gui studied the subject day and night.

As before, he practically lived in the library.

I take a short nap during the day and then continue to refine it after waking up.

The dim light from the corner of the table accompanied him through one long night after another.

He deduced the overall structure of the virtual image technique again and again, precisely embedding every node of the astigmatism technique into the framework.

When I get hungry, I just nibble on a few bites of bread that's on the corner of the table.

When I get sleepy, I just lie down on the table and take a nap.

He was so focused that he failed to notice some subtle anomalies.

The bread on the table always has a small bite missing from the edge every time I wake up.

It felt like I'd been gently bitten by some small animal.

The water level in the glass was also a little lower than before I went to bed.

The marks were so faint that they would be completely unnoticed unless one was paying close attention.

Lin Gui's attention was entirely focused on the scroll that had been unfurled in front of him.

It was his fourth night back at the Library of the Elements.

The final rune of the Illusionary Realm technique was completed.

Lin Gui put down his pen and looked at the parchment in front of him, which was covered with runes and loops.

Then he closed his eyes and began to chant.

"Light forms the trajectory, guiding my course..."

"A delicate web is woven, and all things shift their course..."

"A thousand mirrors reflect each other, using illusion to represent reality..."

The incantation flowed from his mouth, low and steady.

Magic flowed slowly through his core circuits, spreading out little by little along the newly constructed path.

He opened his eyes.

A place that was originally empty.

A row of bookshelves gradually solidified before his eyes.

Every gold lettering on the spine, every grain of wood, and every curled corner of the page is vividly depicted.

It looks exactly like the real bookshelf next to it.

Lin Gui reached out and touched the surface of the bookshelf with his fingertips.

His hand passed through the illusion.

There was no cool, woody feel; only the slight resistance of fingertips piercing through the void.

That was just a play of light and shadow.

But it looks exactly the same as the real thing.

Lin Gui withdrew his hand, a slight smile appearing on his lips.

Next, we should focus on the Mountain-Breaking Dragon.