Nine terrifying attacks, linking the momentum of wind, fire, and thunder, crashed down simultaneously.

The assault of wind, fire, and thunder had already persisted for some time. Yet, throughout this duration, Lu Yuan had been drawing his sword at his absolute fastest, and even at this peak velocity, every single strike was flawless, entirely perfect—a feat bordering on the unbelievable.

"Sword rise, sword move, sword cleave, sword birth, sword break, sword perish, Sword Flowing Cloud!" Lu Yuan's blade cut through with blinding speed, the final arc slicing out to completely block the core mass of the wind, fire, and thunder.

The Ninefold Heavenly Tribulation of the Samadhi Divine Wind, True Fire, and Heavenly Thunder had officially passed.

What a young man, profoundly accomplished in the art of the sword!

However, everyone instinctively looked upward.

Under normal circumstances, merely encountering one aspect of the Samadhi Divine Wind would constitute the primary heavenly trial for breaking into the World Realm. But clearly, this time was different. Dongfang Ghost Emperor and the others raised their heads, only to see the turbulent, rolling calamity clouds still smothering the sky above the alternate dimension; the clouds had not diminished noticeably despite the descent of the Samadhi Divine Wind, True Fire, and Heavenly Thunder.

Evidently, the trials of the Samadhi Divine Wind, True Fire, and Heavenly Thunder, so terrifying to others, had merely been an appetizer for Lu Yuan.

Such a tribulation was merely an appetizer.

How truly immense must Lu Yuan’s true ordeal be? And based on the principle that a stronger foundation invites a fiercer tribulation, Lu Yuan’s foundation must be exceptionally formidable.

With such a powerful foundation, if he did not perish here, he held the hope of assaulting the Civilization Realm.

The Civilization Realm!

That was a legendary state of existence.

A cultivator in the World Realm could reign supreme within the Central Celestial Dynasty’s domain, but a cultivator in the Civilization Realm could dominate that Dynasty, no longer confined to a single region. Moreover, the greatest advantage of the Civilization Realm was survival even when facing the collapse of an Era—something utterly impossible for those below this level.

Entering the Civilization Realm meant transcending the cycle of Era reincarnation.

Just then, an intensely powerful pressure descended from the calamity clouds high above the alternate dimension. Such crushing might forced everyone to abandon their introspection. What exactly was descending? With a resounding boom, the sky seemed to shatter myriad things.

The calamity clouds descended!

As the clouds passed, everywhere they touched was instantly transformed into an emerald sea.

What kind of tribulation was this, that merely passing over a location turned it into a boundless expanse of green?

Finally, the calamity clouds reached a height visible to all. Lu Yuan looked up and saw what appeared to be an enormous diagram suspended in the heavens—a diagram of staggering scale. Within this array map, ancient and bearing the weight of eons, stood countless colossal, towering trees. There were nations formed of trees, cities composed of trees, rivers woven from trees, and mountains shaped by trees. Living beings of green, weapons forged from wood, and long spears crafted from timber—in this world, everything, absolutely everything, was made of trees. This was a world of wood.

"The Boundless Tree Sea Diagram!" Dongfang Ghost Emperor suddenly roared out!

"The Heavenly Tribulation is the Boundless Tree Sea Diagram!"

In this epoch, the most potent and mysterious artifacts were the Diagrams. Within any ranking of the top five mightiest entities, both 'Tree' and 'Diagram' aspects were assuredly represented.

Each ultimate directional path culminated in a Diagram. For instance, in the previous Sword Era, there was the Myriad Sword Divine Diagram, followed closely by the Immortal Slaying Array Diagram.

Or consider the Primordial Witch Civilization of the first twelve Eras, which possessed the Supreme Primordial Witch Diagram, succeeded by the Twelve Ancestral Witch Diagrams.

Or take the Demon Era of the preceding eight Eras; there was the Night March of the Hundred Demons Diagram, where every single demon was a Heavenly Venerate level or higher, known as Demon Ancestors.

Or look at the first six Eras, often called the Heavenly Mother Era, though this moniker merely reflected the supremacy of the Heavenly Mother Nuwa’s faction. Nuwa herself held two Diagrams: the Universal Motherhood Diagram and the Diagram of Mountains and Rivers (Jiangshan Sheji Tu).

For example, during the Immortal Ancient Civilization of the fifth Era, Hong possessed the Diagram of Purple Heaven Hearing the Dao.

The power of the Diagrams was unimaginably vast.

Within the Tree Civilization, there was a treasure used to anchor the civilization itself: the Boundless Tree Sea Diagram.

And what appeared now was recognizably the Boundless Tree Sea Diagram—no, not the true one. The authentic Boundless Tree Sea Diagram was the primary treasure of the Tree Civilization's Twilight Ruler, powerful enough to suppress even Heavenly Venerates. What now manifested was merely an illusory projection of the Diagram, born from the Heavenly Dao itself.

However, among the heavenly trials for breaking into the World Realm, the most potent manifestation was always the phantom projection of a Diagram.

Lu Yuan was unquestionably facing the ultimate heavenly trial for the World Realm breakthrough.

Unexpectedly, Lu Yuan was confronted by the strongest trial, as the divine Diagram's projection descended from the heavens.

A major function of the Boundless Tree Sea Diagram was its ability to transform anything it encountered—even the void itself—into endless shadows of trees. At this moment, the residual Samadhi Divine Wind in the sky was instantly frozen in place, morphing into a canopy of tree shadows. These shadows carried the fierce momentum of the wind, transforming even the monstrous wind of the Samadhi Divine Wind into timber. How terrifying was this Boundless Tree Sea Diagram?

In the span of a breath, the Samadhi True Fire and Samadhi Heavenly Thunder remaining in the sky were also completely converted into wood.

And the Boundless Tree Sea Diagram continued its descent.

Light Slave Number 3000 and Light Slave Number 2900 ceased their brainwave communications. Both stared intently at the optical computers before them, which flashed with streams of analytical data.

"Sub-diagram of the Boundless Tree Sea Diagram. Function: transforms all entities into trees, erasing all life. Probability of absolute kill against Lu Yuan: ninety-nine thousand nine hundred and ninety-nine out of one hundred thousand. One in one hundred thousand chance of an unexpected deviation." Upon seeing the analysis from the optical computer, Light Slave Number 2900 and Light Slave Number 3000 realized they wouldn't even need to deploy their mechanical life forms; Lu Yuan was doomed.

The computer analysis gave Lu Yuan only a one-in-one-hundred-thousand chance of survival, which amounted to virtually no chance at all. The slaves' thinking relied heavily on their optical computers, and while the computers had exhibited errors before, the failure rate was scarcely one in ten thousand.

Lu Yuan took a deep breath and immediately drew in vast reserves of World Essence Qi into his body. The battle against the Samadhi Divine Wind and its kin had drained him significantly, but thankfully, his supply of World Essence Qi was ample enough for replenishment.

The immense, boundless Boundless Tree Sea Diagram continued to press down.

Lu Yuan summoned his Nourishing Immortal Sword and unleashed a storm of sword qi that pierced toward the Diagram. But any sword qi that touched the Boundless Tree Sea Diagram instantly transformed into individual, sword-shaped trees. This thing was truly terrifying to the extreme; the strongest heavenly trial lived up to its name.

Lu Yuan found himself in an incredibly awkward predicament: confronting the Boundless Tree Sea, which was utterly fixed upon him. He could neither escape nor overcome it. No matter how far he fled, the Diagram followed.

Gritting his teeth, he executed Spatial Lock, striking out instantly. However, the space around him immediately twisted into an endless sea of trees, and the power of the Spatial Lock vanished.

Lu Yuan's sword light flashed like lightning as he unleashed the Sword Intent of Death. But the death qi projected by this intent transformed into a withered, black tree.

Damn it!

As Lu Yuan sensed the danger, his Nourishing Immortal Sword itself was becoming a tree radiating righteous energy. Before Lu Yuan could react, his own body began an irreversible process of tree transformation, as if he were about to become a different species altogether. At that precise instant, Yan Cangtian's hand moved toward his own sword hilt.

If Yan Cangtian intervened to assist, Lu Yuan would not have passed this tribulation, making any subsequent heavenly trials vastly more difficult.

In that split second, a flash of inspiration struck Lu Yuan's mind: didn't this resemble the Wood Dao Holy Qi he previously obtained from Mu Bingyi? The Wood Dao Holy Qi itself originated from the Boundless Tree Sea Diagram, though the true Diagram was infinitely more terrifying than the Holy Qi, beyond all rational comparison.

Then, I will try the Minor Sword Dao Tree, he thought.

Lu Yuan immediately summoned his Minor Sword Dao Tree. Instantly, his own tree began to grow rapidly. Previously, it had only reached just over five hundred zhang. But now, infused by the boundless energy of the Boundless Tree Sea, the Minor Sword Dao Tree surged upward. In the blink of an eye, it surpassed one thousand zhang.

Then, it quickly became fifteen hundred zhang, then eighteen hundred, then two thousand.

Two thousand two hundred, two thousand eight hundred.

It continued to grow relentlessly until it reached three thousand zhang before its ascent finally stalled.

Simultaneously, Lu Yuan perceived that the Heavenly Laws he had comprehended were also increasing at an astonishing pace.

A surge of intensely cold and frosty sword intent flashed through his mind. Not only the one hundred and thirty-fifth Frost Sword Intent, but during the growth of the Minor Sword Dao Tree, he also grasped the one hundred and thirty-sixth intent, Frost Descends; the one hundred and thirty-seventh, Winter Begins; the one hundred and thirty-eighth, Winter Solstice; the one hundred and thirty-ninth, Minor Cold; and the one hundred and fortieth, Major Cold.

At this point, he had fully grasped all twenty-four sword intents required by the Time Iron Rule of the Twenty-Four Solar Terms.

A significant portion of this understanding was achieved by relying on the growth of the Minor Sword Dao Tree.

Of course, merely grasping the twenty-four Solar Term sword intents was not enough to grasp the true Time Iron Rule; one still needed to comprehend the essence of time and its flow. This had always been incredibly difficult, yet all of this—every piece of it—manifested within the Minor Sword Dao Tree, and Lu Yuan understood it almost instinctively.

What, truly, was the essence of time?

Time was the process of transformation in matter, a process that was inherently difficult to reverse.

Aided by the Minor Sword Dao Tree, Lu Yuan could even see, in that single instant, a surging river of time flowing from the deepest reaches of antiquity. The very essence of time lay revealed before him.