The second line of defense had taken a month to construct. While still rudimentary, it was significantly stronger than the first. Stationed at this new line, Lei Dong personally held the front, stubbornly resisting the enemy's surging, tide-like assaults.

Because the line had retreated dozens of li, even more enemies were drawn in—all shapes and sizes, packed densely, numbering at least several hundred thousand. Furthermore, reinforcements continued to pour in. Clearly, the Abyss Lord and the Sacred Radiance King intended to use this momentum to crush Lei Dong outright.

But they had severely underestimated him. Since entering the Abyss Domain, thanks to a massive influx of small Chaos Crystals and Lei Dong's own supply, his elite forces had been in a state of constant metamorphosis. Moreover, the effects of the Grotto-Heaven and Blessed Land amplified this evolution to its absolute peak.

Once Lei Dong fully bared his fangs, even if the Abyss Lord and the Sacred Radiance King exerted their utmost strength, they would never manage to overthrow him. In fact, after a period, it was highly probable that Lei Dong would turn the tables and strike back.

A ferocious battle erupted at the second line of defense.

However, right at the onset, within a radius of a hundred li, violent explosions erupted continuously—it was the massive deployment of Yin Fiend Heavenly Thunders. These so-called Yin Fiend Heavenly Thunders were powerful consumable artifacts created by gathering and refining the Yin Fiend Qi permeating the heavens and earth.

The blast radius of a single Yin Fiend Heavenly Thunder often reached a li. Those caught at the epicenter stood virtually no chance of survival, even Golden Core cultivators. Even those outside the central area would inevitably suffer damage. As for Nascent Soul tier experts, while they might not meet instant death, they would sustain varying degrees of injury depending on the strength of their defenses.

The primary source for Yin Fiend Heavenly Thunders was naturally the Nether Ghost Realm, which held not only Nether Ghost Qi but also countless amounts of Yin Fiend. Lei Dong had an exceptionally strong affinity for these thunders, having relied on them to overcome several crises in his life. This even led him to station dedicated personnel within the Nether Ghost Realm solely to purchase them. An item that once cost around 300,000 spirit stones had now been driven up to 600,000.

Besides this acquisition, Ding Wanyan was also an adept producer of Yin Fiend Heavenly Thunders. She possessed the rare Yin Fiend Physique, making her uniquely receptive to the substance. Furthermore, she practiced the most orthodox Yin Fiend Grand Art of the Yin Fiend Sect.

Even without relying on collecting ambient Yin Fiend, she could convert her true essence into the necessary energy to fabricate many thunders for combat. Of course, thunders instantly condensed like this could not be stored long-term. Fortunately, Ding Wanyan had mastered the true method of refining the artifacts, allowing her to periodically forge storable Yin Fiend Heavenly Thunders whenever she had free time.

To date, she had stockpiled several thousand of these thunders—her true, terrifying trump card. Once she amassed a sufficient quantity, even experts of a higher realm than herself would struggle to escape misfortune.

Combined with Lei Dong’s collected stores, they amassed a total of around six thousand Yin Fiend Heavenly Thunders, strategically planted within the two defense lines, waiting for the perfect moment to deliver a devastating blow.

When the full six thousand thunders detonated beneath the enemy’s feet, the resulting roar was deafening, an auditory terror akin to the heavens collapsing and the earth splitting, causing the very sky and land to drastically change hue. When the noxious mist finally dispersed, a colossal crater, a hundred li across, scarred the ground.

Countless lives were instantly shredded into fragments in that unimaginably violent explosion; not even their souls survived. A vast number of Golden Core experts could not withstand such world-shattering power. Only a small fraction of Golden Core cultivators survived, either through luck or by employing specialized defensive techniques, but even they were severely wounded.

Those who truly survived were mostly Nascent Soul tier experts. Among the twenty to thirty thousand survivors present, several thousand were Nascent Soul, representing the core elite of the Sacred Radiance King’s allied forces. Yet, even the Nascent Soul experts sustained injuries to varying degrees.

This single blast stunned everyone. Even Lei Dong hadn't anticipated that the simultaneous detonation of six thousand pre-positioned Yin Fiend Heavenly Thunders would yield such a heaven-shaking, ghost-moving result. The cannon fodder truly lived up to their name.

However, this single explosion represented a massive financial loss for Lei Dong. Setting aside the ruined spoils of war from the blast, the market value of the six thousand Yin Fiend Heavenly Thunders alone amounted to billions of spirit stones.

The Abyss Lord and the Sacred Radiance King were equally dumbfounded. They had never expected Lei Dong to be so ruthless, nor could they fathom where he had sourced so many Yin Fiend Heavenly Thunders. He had just wiped out half their army in one go.

Of course, by this point, retreat was no longer an option. Both roared into their communication arrays: "Attack! Keep attacking!" Now, they harbored a singular, burning desire: to completely obliterate Lei Dong. Otherwise, they could never quell the rage in their hearts.

The two peak-level figures ceased hiding in the rear, personally leading their armies into the rear of the frontline to supervise and initiate a final, total offensive against Lei Dong.

Lei Dong was momentarily stunned. Damn it, he had intended only to tie up the enemy, but he had clearly overplayed his hand. There was no choice now; the battle raged on. Lei Dong summoned his utmost focus, constantly recalling injured (Hidden Dragon) soldiers and (Fierce Ghost) troops into the Grotto-Heaven and Blessed Land for recuperation, while quietly deploying fresh forces from the Grotto-Heaven to replace the exhausted defenders.

Simultaneously, he initiated communication with the Nether Ghost Emperor, urging haste and immediate reinforcement. With the battle having reached this critical stage, the Abyss Lord and the Sacred Radiance King were unlikely to escape. While Lei Dong could ultimately win by committing all his reserves, the cost would be so exorbitant that even he couldn't bear it.

This entire maneuver was also a test for the Nether Ghost Emperor and the others. If they arrived within a day, it would signify that nothing untoward was happening. Otherwise, Lei Dong would not hesitate to calculate everyone involved into his grand scheme.

The war, at this juncture, descended into its most desperate phase. Nascent Soul tier experts on both sides began to fall continuously.

Fortunately, the Nether Ghost Emperor and his company did not disappoint Lei Dong's trust. Upon receiving his urgent summons, they rushed over at extreme speed, arriving at the periphery of the Bone-Gnawing Cold Pond in only seven or eight hours. Without preamble, they launched a ferocious assault on the rear and reserve armies of the Sacred Radiance King’s coalition.

The Sacred Radiance King was caught completely off guard by the sudden appearance of this enemy. He watched in dismay as Lei Dong’s makeshift fortress, which was already trembling precariously and on the verge of collapse, was about to yield its hard-won fruit, only to have this inexplicable army stab directly into his rear.

Intelligence reports from the chaotic rear reported that this army stabbing their flank was exceptionally powerful and comprised of highly diverse elements: Ghost Clan forces, Demon Dragons, Nether Phoenixes, Purgatory Demons, Flame Elementals, mechanized Puppet Armies, Yakshas, and, naturally, humans. This army totaled only fifty thousand but was staggeringly elite, with perhaps one-tenth of its strength possessing Nascent Soul tier combat capability.

Such a complex composition truly baffled the Sacred Radiance King. Who organized this army? Who was its leader? Was it the Nether Ghost Emperor, or the Purgatory Demon King? Could this be a case of the mantis stalking the cicada, unaware of the oriole behind?

Caught between a wolf in front and a tiger behind, the Sacred Radiance King felt a chilling despair. Was it possible that after all his arduous efforts and immense sacrifices, the Chaos Otherworld he was about to seize would slip through his fingers?

He knew clearly that if he chose to break out to the rear with only a small contingent of personal guards, he might save his own life. However, the Sacred Radiance King was unwilling and too proud to abandon the fight now.

Advancing—only by charging forward with everything could true vitality and a chance to counterattack be found. He needed to endure immense pressure and casualties for a short period, utterly shatter Lei Dong’s defenses, and then utilize the complex terrain of the Chaos Otherworld for guerrilla warfare.

As long as he could hold out in this domain, he held a strong hope of breaking through to the late stage of Soul Transformation, perhaps even beyond…

The Abyss Lord, Udis, was inherently a figure of ambition and cunning. At this moment, he perfectly matched the Sacred Radiance King’s resolution. After a brief exchange, they united in purpose, both leading their personal guards to the very front line, intending to use their supreme power to swiftly break Lei Dong.

Moments later, the battlefield erupted in ferocious shouts. The Nether Ghost Emperor and the Purgatory Demon King, their true identities concealed by the Thousand Illusions Mask, also led their forces charging into the Chaos Otherworld, plunging like a sharp blade into the tail of the Sacred Radiance King’s coalition.

To the Sacred Radiance King’s horror, Lei Dong proved too monstrously capable. Even while facing countless elites crashing into his front lines, he managed to direct his army to firmly hold the teetering, makeshift fortress walls.

"Time waits for no man," the Sacred Radiance King thought with rising desolation, unable to breach Lei Dong’s defenses. Just as he sank into utter despair, mentally preparing to be surrounded and killed, another unexpected event suddenly occurred on the battlefield.

The spatial rift, which had been open for several li, silently sealed itself. Then, in the dim sky behind Lei Dong’s position, dense armies began to stream in. These forces possessed a stern bearing and undeniable might; though only tens of thousands strong, they projected an immense sense of pressure.

The one leading them was an exceptionally tall Abyss Demon. The demonic wings unfurling from his back were fully twice the size of the Abyss Lord's. The mere aura this figure unintentionally exuded sent a palpable sense of impending doom through Lei Dong and the other Soul Transformation level experts present.