... Of course, the sheer power of a supreme-grade spirit ghost, or a Celestial Spirit Ghost, lies not entirely in its inherent strength. It is simply that cultivating and upgrading ordinary spirit ghosts is no easy feat. Not only does one require an exceptional Soul Nurturing Pagoda, but they must also constantly hunt and feed it the flesh and blood of demonic beasts. If a spirit ghost encounters a bottleneck during its advancement, the master must expend vital essence blood for a re-consecration, hoping it breaks through and grows stronger.

It can be said that for an ordinary person to raise a low-grade spirit ghost and ensure it keeps pace with their own advancement requires an immense investment of time, energy, and vital essence blood. If they nurture two, or even three, nearly all of their focus and time must be devoted solely to these spirit ghosts. Thus, spirit ghosts that evolve into ghost soldiers whose ranks match the master’s are undeniably powerful magical assets. However, for the vast majority of cultivators specializing in the Ghost Control Arts, raising too many low-grade spirit ghosts often severely impedes their own cultivation progress. But supreme-grade spirit ghosts are entirely different. A slight nourishment from a decent Soul Nurturing Pagoda, or even just the occasional devouring of demonic beast flesh, allows for rapid promotion, requiring virtually no dedicated nurturing time from the master. Furthermore, the greatest advantage is that the supreme-grade spirit ghost's level can quickly surpass that of its original master, and the chance of it hitting a bottleneck and stagnating for long periods is extremely low.

Consequently, possessing a single supreme-grade spirit ghost allows someone like Lei Dong to effortlessly acquire a ghost soldier several tiers stronger than himself. For instance, with Lei Dong currently at the second level of Qi Condensation, with just a bit of focused effort, a supreme-grade spirit ghost refined into a soldier could quickly advance to the fifth or sixth level. Under such circumstances, Lei Dong's combat effectiveness would naturally be astonishing.

Although low-grade spirit ghosts can also advance continuously, each promotion is comparatively arduous, and they are prone to frequently hitting stagnation points. If too much effort is not invested in their nurturing, low-grade spirit ghosts are very likely to lag far behind their master’s ascent. Over time, the utility of the spirit ghost to its master diminishes significantly.

It is for this reason that possessing an excellent spirit ghost, perhaps even a Celestial Spirit Ghost, grants one an immensely powerful auxiliary force without demanding substantial personal effort.

Though he could not know the current state of the Myriad Ghosts Ancestor's supreme-grade spirit ghost, one thing was imaginable: its individual combat prowess and rank likely far surpassed that of the Myriad Ghosts Ancestor himself.

However, Lei Dong's Soul Devouring Pagoda was an anomaly. The soul beads condensed after devouring vast quantities of Yin Souls could not only create low-grade spirit ghosts but also promote low-grade ones into mid-grade. The only sticking point was the cost: promoting to mid-grade required ten soul beads. Who knew how many would be required to advance from mid-grade to high-grade? A hundred? Or perhaps a thousand? But Lei Dong dared not experiment, as a hundred or a thousand beads were far beyond what he could amass in a short period.

After all, an entire month yielded only about ten soul beads through devouring and creation. Because of this, Lei Dong was quite content with promoting his ghost soldier to the mid-grade tier this time. His own aptitude was not exceptional, and having a mid-grade ghost soldier meant that even if left in a Soul Nurturing Pagoda, it would not fall too far behind his own cultivation level. This, of course, was predicated on possessing a reasonably good Soul Nurturing Pagoda.

Steel-hearted, Lei Dong resolved to remain in Myriad Ghosts City, capturing Yin Souls to refine soul beads, which he would then use to smash out another mid-grade spirit ghost to sell. The probability of encountering a mid-grade spirit ghost was stated to be a staggering one in a million, a hundred times rarer than a low-grade spirit ghost, according to the Ghost Control Arts records. That is to say, with average luck, one might need to encounter over a million Yin Souls to possibly find a single mid-grade spirit ghost.

From this, it was clear that the value of a mid-grade spirit ghost was at least a hundred times that of a low-grade one. As for high-grade spirit ghosts, they were treasures utterly beyond market supply. If one exceptionally lucky instance appeared on the market, it would inevitably draw countless cultivators who practiced the Ghost Control Arts, leading to an astronomical price at auction.

But Lei Dong's supreme advantage lay in the fact that, with a bit of luck, he could manifest a mid-grade spirit ghost in just over a month, securing a price definitely above a thousand spirit stones. Once possessing a thousand spirit stones, acquiring a superior Soul Nurturing Pagoda would become much easier.

Day after day, when the Yin Souls in one mass grave grew scarce, Lei Dong would quickly move to a new location. Fortunately, there were countless gathering spots for common Yin Souls near Myriad Ghosts City, covering hundreds of miles. If one considered the entire area under the Yin Fiend Sect, the number was immeasurable. However, Lei Dong only dared venture into desolate spots that had not been established for more than a century. At his current cultivation level, venturing into those well-known, infamous fiendish grounds might lead to encounters with more powerful wild ghost soldiers or even wild ghost guards, which would be a net loss—and he might even perish there.

Time is the ultimate cultivator. Even those useless low-grade ghosts, if they wander, prey, and survive continuously in Yin Fiend territories for a very long time, will slowly evolve into ghost soldiers, independently consuming flesh and blood, or even other Yin Souls. Over the long haul—say, several hundred or a thousand years—they too will become quite formidable, though their rate of growth is far inferior to that of spirit ghosts.

But the most terrifying entities are those spirit ghosts that survive for ages and evolve into ghost soldiers on their own. Even if not artificially nurtured, given good luck and suitable conditions, spirit ghost soldiers can mature to terrifying levels. With his second-level Qi Condensation strength, he truly dared not wander recklessly, having to confine himself to those mass graves whose histories spanned only a few decades.

After all, the Yin Fiend Sect was inherently an evil sect; they would deliberately cultivate, or even intentionally form semi-artificial mass graves in Yin Fiend territories to facilitate the formation of Yin Souls, providing endless resources for the sect. Moreover, these sites served as training grounds for junior disciples.

Because there were at least hundreds of similar mass graves even within the influence of the Myriad Ghosts Cave, Lei Dong did not fear a lack of low-grade ghost sources in the short term. Nor did he worry that his depletion of low-grade ghosts in an area would draw suspicion. Firstly, low-grade ghosts are cheap, attracting almost no attention. Secondly, few cultivators would bother releasing captured low-grade ghosts back into the wild. At the very least, low-grade ghosts had a few minor uses, the most common being serving as food for spirit ghost servants or being sacrificed to refine magical artifacts like the Myriad Ghosts Banner.

... Boom!

With a deafening blast, a large crater several feet in diameter was blasted into the ground where Lei Dong had stood. Fortunately, Lei Dong, relying on his second-level Qi Condensation cultivation and the Cloud Ascending Boots, had instantaneously leaped away before the Fiend Thunder struck. Even so, a glance at the resulting blast pit made Lei Dong break out in a cold sweat, his face paling slightly.

The Bloodthirsty Ghost Soldier let out a sharp cry, raising its shield to bat away a rank-two wild ghost soldier that had nearly harmed its master. With flashes of blade energy and swirling Yin winds, it fiercely entangled the foe.

When the ghost soldier first detected the rank-two wild ghost soldier, Lei Dong had been immensely pleased. He commanded the Bloodthirsty Ghost Soldier to engage it while he stayed back, attacking with the dark-green small sword. However, he never anticipated that this wild ghost soldier possessed such an astonishing innate magical art as Fiend Thunder, which nearly vaporized the overconfident Lei Dong with a single strike.

Watching the rank-two wild ghost soldier being forced back repeatedly by the Bloodthirsty Ghost Soldier, its ghostly wails incessant, Lei Dong wore an expression of regret. A wild ghost soldier possessing such an innate spell must have evolved from a spirit ghost. Yet, once a spirit ghost evolves into a soldier on its own, although it can be captured and placed in a Soul Nurturing Pagoda, it cannot be bound as a blood-sacrificed servant using the Ghost Control Arts.

However, it wasn't as if this wild ghost soldier was entirely useless. The Yin Fiend Sect possessed another Ghost Controlling technique specifically for gathering these lone, wild ghosts to refine into a Myriad Ghosts Banner. The most powerful Myriad Ghosts Banners, when deployed in combat, unleash myriad ghosts simultaneously in a magnificent and potent display. But because the wild ghost soldiers had already developed rudimentary sentience, their intelligence had to be refined and erased first, leaving only their base instincts. Consequently, the ghost soldiers refined into a Myriad Ghosts Banner are far inferior in combat strength to blood-sacrificed ghost soldiers. Furthermore, even those ghosts originating from Celestial Spirit Ghosts, once refined via the Myriad Ghosts Banner, stand almost no chance of further advancement.

This was the source of Lei Dong’s regret. To obtain a blood-sacrificed ghost soldier, one must refine and merge with the spirit ghost while it is still in the Yin Soul state, before its sentience fully awakens. Nevertheless, while this wild ghost soldier could not be recruited as a subordinate, it served as an excellent source of nourishment for the Bloodthirsty Ghost Soldier. After regaining his composure, Lei Dong cautiously urged the dark-green small sword, transforming it into a streak of emerald light, and drove it fiercely toward the wild ghost soldier.

... (Newcomer writer, new book, I ask all my brothers and sisters, while you are feeling a bit of satisfaction and enjoyment, please cast a recommendation vote or two. This will be very beneficial for the growth of my book. Thank you all!)