While the player is in Battle Through the Heavens, the system is in The Great Ruler.

Chapter 244 The Black Demon Lightning Appears! Double Happiness!
A few days later, at the summit of Tianmu Mountain.

Lu Yu sat cross-legged, with hundreds of jade boxes radiating energy fluctuations neatly arranged in front of him. With a slight thought, a dark, ink-like flame rose from his palm—the Netherworld Flame.

By this time, the Tianshan Terrace on the mountainside had already been filled with people.

All the alchemists from the Spirit Treasure Pavilion held their breath, their eyes fixed intently on the mountain peak. Xiao Yan stood at the very front of the crowd, his eyes filled with anticipation and awe.

In a small courtyard a little closer, Mang Tianchi and Gu Yuan stood side by side.

Mang Tianchi stroked his beard, his eyes gleaming: "Ninth-grade pills... I never expected to see such a grand event outside of the Pill Tower and the Eight Ancient Clans."

Gu Yuan remained calm and said, "It's just an experiment. Even a ninth-grade alchemist wouldn't dare guarantee success on the first try. This young man has good talent in formations, but the art of alchemy is vast and profound. Everyone has their strengths, and it's impossible to excel in everything..."

At the mountaintop, Lu Yu seemed oblivious to the spectators in the distance, his entire mind absorbed in alchemy.

As his hand seals changed, the jade boxes in front of him opened one after another, and medicinal herbs flew out one after another, quickly covering the sky above his head. At a rough glance, there were probably no less than several hundred kinds.

Such a massive quantity left the alchemists at Lingbao Pavilion dumbfounded, unable to help but gasp in astonishment.

"This...this quantity of medicinal herbs is terrifying!" a seventh-grade alchemist murmured.

Xiao Yan's gaze was intense as he murmured, "As expected of a ninth-grade pill..."

Ignoring everyone's astonishment, Lu Yu lightly tapped the air with his finger, and numerous medicinal herbs instantly separated from the torrent of herbs, quickly pouring into the Azure Phoenix Cauldron before him, where they were devoured by the Netherworld Fire within.

In the sky, countless medicinal herbs, under Lu Yu's control, formed a continuous line and were poured into the medicine cauldron. In just a few minutes, a terrifying energy fluctuation emanated from the cauldron, causing the surrounding space to ripple.

The blazing black flames completely enveloped the medicine cauldron, resembling a giant fireball. Every few minutes, small fireballs would emerge from the cauldron, hovering and circling it. Each of these fireballs contained medicinal liquids and powders of different colors, all refined to the highest purity.

"This refining speed...it's unbelievable!"

Mang Tianchi finally couldn't help but exclaim in amazement, "Every drop of the medicinal liquid is incredibly pure, such control..."

Gu Yuan narrowed his eyes slightly and nodded, saying, "It's indeed not bad..."

When the number of floating fireballs around Lu Yu's cauldron reached several hundred, he finally stopped. All the medicinal herbs had been refined in just half an hour!
Amidst the astonished gazes of the crowd, Lu Yu took out two specially crafted jade bottles. The moment the stoppers were opened, the sounds of dragon roars and phoenix cries resounded through the sky, and a drop of dark golden ancient dragon essence blood and a drop of shimmering purple ancient phoenix essence blood slowly rose.

"melt!"

Lu Yu let out a low shout, and the Netherworld Flame enveloped the two drops of essence blood. Under the tempering of the frigid flames, it transformed into a ball of purplish-gold liquid.

Then, with a thought, the hundreds of clumps of liquid medicine floating around him seemed to be summoned and poured into the purple-gold liquid one by one.

The primordial energy of the entire Tianmu Mountain surged wildly towards its summit, and under the exquisite control of the Netherworld Fire, all the medicinal power perfectly fused together. The Ninth-Grade Precious Pill—the Dragon-Phoenix Supreme Pill—finally began to condense!
At the mountain peak, Lu Yu's expression was solemn as he rapidly formed hand seals. The purplish-gold liquid, enveloped by the Netherworld Flame, slowly swirled, absorbing hundreds of medicinal liquids around it. With each liquid it absorbed, the dragon-phoenix phantom on the surface of the liquid solidified, emanating an increasingly terrifying pressure.

Time slipped away quietly in the silent refining process, and half a month had passed in the blink of an eye.

During this time, everyone on Tianmu Mountain stayed by his side without leaving for a moment. Even the weakest fifth-grade alchemist, despite his exhaustion, was unwilling to miss this once-in-a-lifetime opportunity to observe.

“It’s been half a month already…” Mang Tianchi looked at the figure on the mountaintop who had been maintaining the hand seal posture, his tone filled with amazement, “Such a long process of condensing the pill, it truly deserves to be a ninth-grade pill.”

Gu Yuan's gaze was profound as he said calmly, "The higher the quality of the pill, the longer it takes to develop. It seems that once this pill is formed, its quality will likely exceed our expectations."

The moment he finished speaking, the space above the mountain peak suddenly fluctuated violently.

"Boom——"

The once clear sky suddenly darkened, with dark clouds gathering wildly from all directions, lightning flashing and thunder roaring. A chilling pressure from heaven and earth instantly enveloped the entire Tianmu Mountain Range!
"Danlei is finally coming!"

An uproar erupted on the Tianshan Platform. Everyone felt the earth-shattering aura, and many alchemists with weaker cultivation turned pale and retreated repeatedly.

Above, the clouds were as black as ink, thick and heavy, shrouding the entire sky in deep darkness. What was unsettling was that there was not a single sound of thunder emanating from these dark clouds. Yet, when everyone's gaze fell upon those deep, seemingly all-consuming clouds, even their very souls trembled slightly.

"This...this is the legendary Black Demon Lightning?"

Upon seeing this scene, many alchemists' pupils suddenly contracted, and their voices trembled with disbelief.

A murmur of unease suddenly arose from the crowd:

"It is said that the power of the Black Demon Lightning is enough to kill a Dou Sheng powerhouse..."

"The last time the Black Demon Lightning appeared, it razed the entire mountain range to the ground!"

"Although the Pavilion Master's alchemy skills are extraordinary, refining ninth-grade pills consumes a great deal of energy, and then facing this Black Demon Lightning..."

Just as everyone was filled with worry, Mang Tianchi clapped his hands and laughed, turning to the old man in blue beside him and saying, "Old Gu, it seems you misjudged him this time. Not only did Lu succeed, but he also summoned the Black Demon Lightning!" Gu Yuan remained standing with his hands behind his back, his aged face expressionless, though a barely perceptible ripple flickered deep in his eyes. He nodded slightly, his tone as calm as if he were discussing a trivial matter: "To be able to summon the Black Demon Lightning, he certainly has some skill."

These words, spoken casually, drew angry glares from all the alchemists present.

"Elder Gu, your words are far too disrespectful to the Pavilion Master!" A white-haired old alchemist couldn't help but speak up. "A ninth-grade pill, Black Demon Lightning, how can 'having some skill' describe this?"

Gu Yuan didn't even lift his eyelids, and said indifferently, "I have seen more geniuses than you have refined pills."

Another middle-aged alchemist said indignantly, "You are far too arrogant! At your age, Pavilion Master Lu can refine ninth-grade pills; there is no one else like him in the entire Central Continent!"

"The Central Plains are vast, but the world is even larger."

Gu Yuan remained unconcerned, but his gaze swept across the mountain peak with a meaningful look. "However... since you have so much confidence in him, why worry about this Black Demon Lightning?"

At this moment, an elder from the Lingbao Pavilion spoke with great concern: "The Black Demon Lightning is no ordinary weapon; what if Pavilion Master Lu cannot withstand it..."

"Couldn't withstand it?" Gu Yuan finally revealed a faint smile. "Do you really think that someone who can refine ninth-grade pills wouldn't be unprepared?"

Just as everyone was wondering, Lu Yu suddenly stood up on the mountaintop. A vast and powerful aura swept out from his body, causing the entire Tianmu Mountain to tremble slightly.

"This is... a Dou Sheng?!"

"The Pavilion Master has actually broken through to the Dou Sheng realm?"

Everyone present involuntarily held their breath, and even the previously indignant alchemists were dumbfounded.

Gu Yuan nodded slightly, his tone remaining calm: "Now, are you still worried that he can't withstand the Black Demon Lightning?"

At the summit of Tianmu Mountain, Lu Yu waved his sleeve, causing the Floating Pagoda to swell in the wind, its body wreathed in endless streams of ghostly fire. He looked up at the terrifying black lightning in the sky, his eyes showing no fear.

The moment the first bolt of pitch-black lightning struck down, the Floating Pagoda soared into the sky, colliding violently with the destructive lightning. Amidst the deafening roar, the black lightning was shattered, transforming into countless black bolts of electricity that scattered in all directions.

Just then, the Meteor God Sword within Lu Yu's dantian suddenly emitted a clear and melodious sword cry. He pondered for a moment, then nodded slightly, and a stream of crimson light shot out in response, joining the Floating Pagoda to meet the successive strikes of black demon lightning.

One way, two ways, three ways...

Nine bolts of black lightning were shattered in succession by the Floating Pagoda, and the dissipated lightning energy was absorbed by the Fallen God Sword. As the last wisp of black lightning entered the sword, the dark clouds in the sky finally dissipated slowly.

Lu Yu raised his hand to retrieve the Floating Pagoda. Just as he was about to recall the Fallen God Sword, he suddenly sensed something—as his natal sword, he clearly perceived that the Fallen God Sword was undergoing a fundamental transformation.

The Meteor God Sword, suspended in mid-air, radiated a dazzling crimson light, its originally blood-red blade gradually transforming into a crystal-clear texture. A faint, sharp sword aura flowed along its tip, emanating a vast and terrifying pressure.

"call out--"

With a whooshing sound, the Fallen God Sword transformed into a streak of light and landed in Lu Yu's palm. He gently stroked the sword, feeling the surging power within, and a smile of satisfaction appeared on his lips.

After countless trials and tribulations, the Fallen God Sword has finally been upgraded to a true divine weapon!

At the same time, the thick, dark clouds in the sky finally began to dissipate slowly. As the clouds dispersed, countless gazes instantly focused on the mountaintop.

The young figure stood with his hands behind his back, unharmed by the terrifying black lightning.

"Roar!"

Just as the dark clouds in the sky dissipated, the Azure Phoenix Cauldron below suddenly burst forth with a dazzling light. Accompanied by a clear and melodious cry, a stream of light shot into the sky from within the cauldron, manifesting in the air a strange creature with a dragon's head and phoenix wings, covered in seven-colored scales, surrounded by a fragrant aroma of elixir.

"The elixir has materialized! It's actually a legendary elixir beast!"

"As expected of a ninth-grade elixir!"

A gasp of surprise erupted from the viewing platform halfway up the mountain; everyone was unable to hide their excitement.

In the courtyard, Gu Yuan stood with his hands behind his back, his gaze slightly narrowed, a hint of surprise flashing in his eyes.

The form of this pill beast... seems to bear some resemblance to the ancient dragon-phoenix recorded in ancient books?
Above the sky, the Dan Beast flapped its wings as if about to take flight, its body radiating light, and it was about to break through the air and disappear.

"Want to go?"

Lu Yu's gaze sharpened, and before he could even make a move, the Meteor God Sword in his hand spontaneously emitted a clear and melodious sword cry. The crimson sword light streaked across the sky like a startled swan, precisely slashing towards the pill beast.

As the sword light flashed, the beast let out a mournful cry, its form gradually dissipating until it transformed into a purple-gold pill that floated in mid-air. The next moment, the Fallen God Sword, carrying the pill, gracefully returned and landed steadily in Lu Yu's palm.

(End of this chapter)