Having grasped all the relevant knowledge, Lei Dong began to attempt modifications to the formation within the Ming Yan You Gui Fan (Netherflame Ghost Banner). This wasn't to say that Lei Dong’s knowledge and skill had surpassed the Artifact Refining Grandmaster Wang Lei.

It was just that Lei Dong’s method of modification was solely aimed at making this Ghost Banner more suitable for his own use, better aligning with his habits and expectations. At best, it was akin to buying a car and giving it a personal tune-up. Asking him to forge one from scratch, however, would likely prove extremely difficult.

The focus of the modifications was mainly on the Artifact Spirit and the Ghost Soldier Forging Array. The former, due to Wang Lei’s inherent limitations, had not allowed for the refinement of an Artifact Spirit possessing indestructible sentience. The latter involved primarily altering and augmenting certain forging arrays, imprinting specific rules concerning the nether ghosts onto their very instincts through the forging process.

The latter point was particularly challenging, as it overlapped with a portion of array design. Fortunately, having a seemingly omnipotent Artifact Soul Deity nearby, Lei Dong quickly formulated a modification plan with its constant guidance and assistance.

During this process, some of Lei Dong’s unconventional ideas managed to startle the Artifact Soul, much as his discussions with Wang Lei had done in the past.

Lei Dong’s underlying concept was simple: if the forging array could brand rules onto the nether ghosts' instincts, then he could devise his own set of procedures. After all, Lei Dong was a transmigrator, and since advancing to the Nascent Soul stage, some vague memories from his previous life—those tucked away in forgotten cellular corners—now felt exceptionally clear and vivid.

By integrating the knowledge he had gained from university and life in his past world with what he was learning now, Lei Dong formed a logical system that was easy to grasp. Compiling rules was comparable to learning to program in C language during his past life's computer science courses. However, the method of compiling rules within the array system was far more complex than the computer languages he had studied without truly comprehending them; it pointed more directly toward the essence of things.

This was because the logic within the array system, once compiled, could resonate with, drive, and utilize the Laws of Heaven and Earth. Imprinting these onto the nether ghosts’ instincts was like installing a software program onto a computer, or perhaps directly writing a set of programs into a robot.

As a result, those obscure and deliberately confusing elements within the array system became crystal clear.

Lei Dong first designed several distinct Imprint Rules according to his needs, allowing him to forge nether ghosts according to different requirements at any time. The first type was named the Suicide Ghost. These nether ghosts possessed extreme speed and understood two simple spells: one for acceleration and one for self-detonation. The former could make them burst forth with astonishing speed within ten breaths. The latter spell, as the name suggested, detonated all internal energy, including their soul power and that single thread of Nine Nether Ghost Flame.

The rationale behind the Suicide Ghost was that since nether ghosts served as cannon fodder, an unknown number would perish in any battle. It was better to let them create a spectacular finale in their final moments. The idea was inspired by the Kamikaze Bats from a strategy game he enjoyed in his past life, StarCraft. Of course, this was purely a design; Lei Dong had not yet tested precisely what startling effects the Suicide Ghost could manifest.

The second type was called the Ferocious Ghost. This ghost differed little from previous nether ghosts, balancing offense, defense, and speed. However, Lei Dong endowed it with two spells through rule compilation: one was the Nether Shield, and the other was the Bloodthirst Art. The Nether Shield, as the name implied, absorbed Nether Ghost Qi to form a faint protective layer on its surface, increasing its survivability. The Bloodthirst Art allowed it to erupt with superior close-combat capability for a short duration. Furthermore, Lei Dong granted it some innate combat instincts, preventing it from mindlessly rushing forward to bite and tear. The Ferocious Ghost was designed as a primary combat unit.

The third type was the Nether Missile Ghost. It could utilize Lei Dong’s Nether Ghost Qi, combined with that thread of Nine Nether Ghost Flame, to launch volleys of Nether Fire Bombs for ranged attacks against enemies. Its speed, defense, and melee capabilities, however, were weaker.

The fourth type Lei Dong dubbed the Belly Cannon Ghost. The rules endowed it with a large abdomen capable of absorbing significant amounts of Nether Ghost Qi and Nine Nether Ghost Flame. It was slow and poorly defended, but it featured an extreme design: the ability to exhaust all its Nether Ghost Qi and Nine Nether Ghost Flame at once to fuse into a single Nether Fire Cannonball for a maximum-damage strike.

The reason for designing so many unit types was twofold: firstly, Lei Dong hoped for multi-unit cooperation to adapt to different enemies. Secondly, Lei Dong also intended to design a super-unit capable of both ranged and melee combat, high speed, invisibility, and artillery fire. However, this was ruthlessly dismissed by the Arena Artifact Spirit instructor.

Between Heaven and the vast universe, there are countless rules and laws. If one cannot reach a state that transcends these laws, one must abide by them. Although Lei Dong’s Ming Yan You Gui Fan was a level of Innate Spiritual Treasure, it still possessed inherent operational limits.

Normally, using a low-grade Yin Soul as the primary material, infusing it with Nether Ghost Qi, Nine Nether Ghost Flame, the Demon Dragon's demonic energy, and a trace of Chaos Spiritual Qi, the resulting finished product would only reach the level of the nether ghosts Lei Dong previously used. This was the rule; unless Lei Dong upgraded the Ghost Banner's quality—for instance, by using a Chaos Origin as material—the ability to elevate a low-grade Yin Soul to its current level was already the pinnacle.

Of course, if a Golden Core-level soul were used directly for forging, or if the resulting Ghost Soldiers evolved by devouring vast amounts of flesh and soul essence, that would be another matter entirely.

Previous nether ghosts were relatively balanced in all aspects. If total capability was considered one hundred percent, Lei Dong had merely shifted some capability from one area to another. Enhancing one aspect inevitably required weakening another. Take the Suicide Ghost, for instance; it possessed almost no defense and exploded upon contact.

But it had to be admitted that Lei Dong’s designs were quite ingenious. Even the demanding and verbose teacher, the Arena Artifact Spirit, praised the novelty of Lei Dong’s ideas and assisted him in completing these designs. Otherwise, relying solely on Lei Dong, fully realizing them would have been difficult.

Once the design phase was complete, implementation and testing were necessary. Design was just theory; it required practical application for validation. Lei Dong decided to first test the Suicide Ghost, a ghost soldier that seemed poised to destroy the enemy while annihilating itself. But as mere cannon fodder, what was there to fear?

Having interacted with Lei Dong for some time, the Artifact Spirit had become thoroughly intrigued by his novel ideas and enthusiastically used artifact refining techniques to slightly modify the Ming Yan You Gui Fan, enabling it to forge Suicide Ghosts. In essence, it was still forging nether ghosts, but the attributes of those ghosts were completely rewritten.

Lei Dong first commanded a batch of one hundred to be forged simultaneously, but he didn't realize the problem until he began the process. Lei Dong had set the capacity for Nether Ghost Qi and other energies the Suicide Ghost could carry slightly too high, exceeding the tolerance of the low-grade Yin Souls.

Bang, bang, bang—over seventy exploded immediately, with only about twenty possessing slightly stronger innate qualities barely enduring the process. At this rate of expenditure, Lei Dong felt it was unsustainable. The depletion of low-grade Yin Souls was irrelevant; they could be captured. However, the Ghost Banner could not withstand this level of attrition. After all, the energy drawn from the Demon Dragon, the Nine Nether Ghost Flame, and the Chaos Essence Iron was finite, not endless.

Fortunately, the first two were Nether-type entities and could recover slowly on their own or by Lei Dong injecting Nether Ghost Qi for absorption and conversion. But the depletion of the sliver of Chaos Spiritual Qi drawn from the Chaos Essence Iron was something Lei Dong could ill afford.

It was only after thoroughly understanding the Ghost Banner that Lei Dong realized forging a nether ghost consumed a minute amount of Chaos Spiritual Qi. While minuscule, the sheer quantity consumed was staggering. Fortunately, the inheritance from Wang Lei used ancient refining techniques, which were exquisite. Upon the Chaos Essence Iron body of the Ghost Banner, Wang Lei had inscribed a miraculous array. Through this ancient micro-array, the Chaos Essence Iron, a spiritual object of Heaven and Earth, would autonomously and extremely slowly attract wandering Chaos Primordial Spiritual Qi from the cosmos to replenish the expenditure at a snail's pace.

This was a feature possessed by the vast majority of Innate Spiritual Treasures. The problem was that Chaos Spiritual Qi was exceedingly sparse in the current era, making replenishment agonizingly slow. But having some replenishment was better than none.

It was no wonder that the strength of the ghosts forged by the Ghost Banner far surpassed the cannon fodder ghosts created by ordinary Ten Thousand Ghost Banners—it was due to that tiny trace of Chaos Spiritual Qi at work.

With this understanding, Lei Dong could no longer afford the lavish, unrestrained consumption of Chaos Spiritual Qi he exhibited previously; he had to account for every drop.

Lei Dong and the Artifact Spirit were compelled to redesign the Suicide Ghost, dialing down some of its attributes. After another bout of intense work, they revised the Ghost Banner's forging array.

This time, the results were much better. Out of one hundred forged, only a handful were overloaded and destroyed during the refining process. For the moment, further modifications were unnecessary. With over a hundred Suicide Ghosts now at his disposal, he had to test their might.

And outside the You Ming Hei Sha Formation (Netherworld Black Fiend Array), a perfect target presented itself.

Lei Dong had been consumed by this back-and-forth tweaking for nearly a year. During this year, the Grand Ancestor of the Taishang Sect, Xuan Yuan Zhenren—the pinnacle of humanity—had endured a miserable existence.

The Fair Arena space was not infinite, covering only about ten square miles. Both parties appeared at the center of the arena, where the You Ming Hei Sha Formation was deployed.

Consequently, no matter which corner the Ancestor hid in, he was never more than four or five miles from the You Ming Hei Sha Formation. A mere teleportation by Xiao You, who had mastered spatial laws, could bring her instantly back into the formation.

For an entire year, Xuan Yuan Zhenren had not dared to close his eyes, his spirit remaining perpetually vigilant against sudden attacks. Because the moment he relaxed his guard, various long-range magical attacks would rain down upon him.