Gradually, a primary cultivation technique surfaced in his mind, named the Heavenly Demon Transformation (Tian Mo Bian). This demonic art was one of the most authentic ancient demonic techniques. Normally unlearnable, it could only be acquired through the inheritance of an Imperial Demonic Seed (Di Mo Zhong) from a great Demon Emperor of a past generation. The technique was vast and complex, but thankfully, Lei Dong had already received the inheritance of the Imperial Demonic Seed, meaning he only needed to carefully ponder it to grasp its superficialities.

However, achieving complete mastery and refining it to perfection would likely not be so simple. Firstly, the Heavenly Demon Transformation was exceedingly intricate; secondly, due to the limits of his current cultivation level, Lei Dong could not unleash its full power.

Even so, Lei Dong vaguely sensed that the Heavenly Demon Transformation should be more potent than some of the top-tier Great Arts of the Yin Sha Sect.

In addition to the primary Heavenly Demon Transformation technique, there was a series of supplementary spells. These would require Lei Dong to slowly comprehend them one by one after diligently cultivating the main technique. This differed from some spells of the Yin Sha Sect, which could still be cast without their matching Great Art, albeit with diminished power. But certain spells within the Heavenly Demon Transformation were contingent upon first mastering the core technique before they could be deployed.

In this desolate mountain wilderness, a place starved of spiritual energy, Lei Dong resolved to stay put for several months to thoroughly digest the knowledge of the Heavenly Demon Transformation lodged in his mind. Perhaps to prevent the successor from forcefully cultivating later stages while still too weak, the Imperial Demonic Seed only transmitted one transformation to Lei Dong’s mind for now. Only after mastering this initial transformation would he be able to obtain the subsequent ones from the Seed.

Time seemed to fly by.

At night, Lei Dong practiced Qi refinement while meditating, relying on mid-grade spirit stones and the Small Five Elements Pills (Xiao Wu Xing Dan), each costing a medium spirit stone, to sustain him. Even in this place devoid of ambient spiritual energy, Lei Dong’s cultivation speed was not slow. Of course, the rate at which spirit stones were consumed was significantly faster.

During the day, he devoted himself to unraveling the profound mysteries of the Heavenly Demon Transformation.

Barely a month later.

Lei Dong had begun to grasp the first transformation of the Heavenly Demon Transformation: Peerless Under Heaven (Tian Xia Wu Shuang). As the name suggested, this was a state of mind, an attitude of absolute supremacy, "None above, none below, save me." Only with such a mindset, an outpouring of boundless arrogance, could one truly comprehend this level and master the first transformation.

Profound Yin True Qi (Xuan Yin Zhen Qi) was already one of the most orthodox cultivation methods of the Demonic Path. Using it to fuel the Heavenly Demon Transformation was supremely suitable.

Lei Dong meticulously contemplated the intent of the Peerless Under Heaven state of mind that the previous Demon Emperor had infused into his mind via the Imperial Demonic Seed. Each time he delved deep into comprehension, a surge of proud spirit would slowly ignite within Lei Dong’s heart. His eyes grew calm yet proud. Simply standing there with his hands clasped behind his back exuded an aura capable of commanding storms and looking down upon the world.

Throughout this month, it had been extremely arduous for Lei Dong to even reach or simply simulate this state of mind. Fundamentally, while Lei Dong possessed an innate pride and an unyielding backbone, these qualities were deeply buried beneath his intensely cautious nature. Only when his deepest sense of self-respect was truly provoked would that wild arrogance surface.

For instance, when dealing with Tian Mo, Lei Dong found it impossible to humble himself before her.

Fortunately, the faint traces of experience transmitted by the former Demon Emperor proved immensely helpful, and Lei Dong’s comprehension was exceptional. When he truly could not grasp the Peerless Under Heaven state of mind, thinking of Tian Mo served as a surprisingly effective catalyst.

Lei Dong spent the entirety of every daylight hour continuously simulating and experiencing the Peerless Under Heaven state. From the initial difficulty and inability to enter the state, it progressed until Lei Dong could achieve a preliminary entry merely by settling his thoughts for a short moment.

Within his body, the Profound Yin True Qi continuously circulated, driving the Heavenly Demon Transformation technique. Gradually, his heartbeat accelerated, and Lei Dong's skin began to flush a ruddy hue. Immediately following, his heart pounded faster and heavier. His expression shifted from placid to one of burgeoning pain, and his breathing grew heavy and rapid.

Yet, this agony seemed to last only an instant. His blood appeared to begin boiling. A profound sense of exhilarating comfort, one that felt ethereal and divine, resonated within his soul, causing his entire body to tremble uncontrollably. As his blood grew hotter, Lei Dong felt an intense pressure building in his chest, compelling him to unleash a ferocious roar.

Echoes reverberated, shaking fragments from the cliff walls of the desolate cave.

It felt as though a stifling, pent-up energy in his chest had been swept clean, replaced by an incomparably thrilling and cathartic sense of release.

Lei Dong clenched his fists, feeling an inexhaustible power surge through his entire body. He harbored the internal conviction that, if he wished, he could shatter everything. His blood raced throughout his system, and his skin was faintly shrouded in a layer of cyan light. Lei Dong merely stamped his foot, and his body shot forward like a cannonball.

Boom!

He slammed heavily into the cave ceiling, causing stones to crack and fall, yet Lei Dong sustained not a single scratch. Floating beneath the ceiling, he felt only exhilaration, an endless well of power demanding release.

If Lei Dong could have seen his own face and eyes at this moment, he would have noticed a faint, almost imperceptible smile, one laced with a flavor of bloodlust. His gaze held an air of supreme arrogance, yet it was intertwined with intense malice and murderous intent.

Crack!

Lei Dong sharply pushed off the ceiling with his foot, plunging downward, only to execute an impossible mid-air somersault, planting both feet back on the ground. With a resounding crash, the stone floor fractured into pieces. Simultaneously, Lei Dong shot straight out of the wild cave, abruptly turning and rocketing directly towards the clouds.

His speed was at least more than double that achieved when using Ghost Shadow Evasion (Gui Ying Dun). Of course, it lacked the grace and elusiveness of Ghost Shadow Evasion. After unleashing the Heavenly Demon Transformation, his entire mentality, actions, and will to fight were completely transformed. Lei Dong felt boundless desires clamoring for release and infinite, inexhaustible strength within his frame.

A massive boulder, half a zhang wide, was pulverized by a single punch. A towering ancient tree, requiring several people to encircle, collapsed as he brutally rammed it with his shoulder and elbow, its fibers tearing apart. A waterfall spanning several zhang wide momentarily halted under the impact of his palm.

Such offensive power was far beyond what a cultivator at the first layer of Foundation Establishment could achieve. Lei Dong destroyed everything he encountered. Only after seizing a passing, brightly colored tiger, tearing it in half, and drinking the blood in great gulps, did the Profound Yin True Qi in his body seem to burn out completely. The cyan glow enveloping him rapidly receded. His eyes and face, in that instant, became utterly drained.

It seemed as though in the span of a mere incense stick’s burning time, all of Lei Dong’s energy had been consumed, even overdrawn. Slumping to the ground, his heightened state of mind returning, Lei Dong gasped for breath. The Heavenly Demon Transformation burned not just Profound Yin True Qi, but also Lei Dong’s physical stamina. At this moment, he lacked the will to even move a muscle, let alone cultivate Qi refinement. Every bone in his body felt shattered, the pain nearly driving his spirit to collapse. All his strength was depleted. The Heavenly Demon Transformation was like an insatiably demanding siren, draining Lei Dong bone-dry.

Of course, Lei Dong knew this method was unsustainable. Forcing himself through the illusion that every meridian was bursting and every bone had turned to dust, he managed to sit down cross-legged, barely swallowing a Small Five Elements Pill, grasping a mid-grade spirit stone, and began to practice Qi refinement.

Several hours later, Lei Dong stood up again, his spirit fully restored, a subtle joy flashing in his eyes. This session of meditation seemed to have resulted in significant progress, equivalent to four or five days of normal sitting practice.

Cultivators understood that when True Qi is excessively depleted, subsequent Qi refinement meditation yields better results. But this improvement was usually minimal. The issue was that completely exhausting all True Qi required tremendous effort and time, not to mention the endless mental torment it inflicted.

To gain a slight edge in cultivation speed, one had to endure significant time and mental suffering—few people chose this path. Of course, certain sects who deemed themselves righteous did resort to this, such as the Vajra Temple (Jingang Si). The practitioners of Vajra Temple were notoriously harsh on themselves, but one had to admit their prowess, especially in terms of willpower, surpassing other top-tier sects.

However, the effect Lei Dong achieved this time was far superior to the results of self-induced exhaustion. This single day yielded the cultivation benefit of several days.

A thought stirred in Lei Dong’s mind: could he utilize this method? It would speed up his cultivation while not delaying his practice of the Heavenly Demon Transformation. Yet, rooted in caution, Lei Dong first checked himself for any residual issues. After meticulous inspection, he only felt lingering soreness in his bones, muscles, and meridians; nothing major seemed amiss.

In truth, Lei Dong himself was unaware of a fundamental difference. During typical cultivator combat or self-initiated spell casting, internal energy is expended. But while True Qi appears concentrated in the Dantian, it is, in reality, dispersed throughout every corner of the body, within every single cell. Thus, 'True Qi exhaustion' often means the Dantian’s reserves are not completely empty.

This explains why, during life-or-death struggles, some cultivators, despite seemingly running out of True Qi, can unleash a final burst, and sometimes even another burst after that—this is them utilizing the reserve energy scattered throughout their bodies, not the absolute emptiness of the Dantian. Especially at the most critical moments of life, more power often erupts. This comes from the reserve strength slowly accumulated through routine practice.

But drawing out this reserve energy for no reason is exceptionally difficult, intensely painful, and requires extremely self-abusive methods to barely achieve.

The Heavenly Demon Transformation, however, was different. As one of the mightiest ancient Demonic Path techniques, when unleashed, it burns everything burnable to achieve a massive, terrifying surge in power within a short span—it is akin to fighting for one’s life at every moment.