Azure Profound Fiend

The advancement speed and combat power of this "Black Fiend Technique" depended entirely on the number of souls refined. As long as one had enough cultivators' Divine Souls or Vengeful Spirits, one could rapidly advance without end.

Its power might not be high at the beginning, but the further one progressed, the more formidable it became.

However, if one did not refine souls to cultivate, then this Black Fiend Technique was merely a foundational transitional technique for ordinary Outer Sect Disciples of the Soul Devouring Sect.

It was wholly a technique that had to be piled up with cultivation resources. Yet just reaching the level of Nine Nether Soul Slaughtering Fiend required a great number of cultivators' Divine Souls or vengeful spirits and evil ghosts—or else an oceanic amount of ordinary mortal soul resources.

For a Qi Refining Stage cultivator, success was practically impossible.

It was precisely these various restrictions that meant few people had ever chosen to cultivate the Black Fiend Technique. Most merely used it during the transitional stage before switching to another technique later.

Thus, when Zheng Yi had ultimately chosen the Black Fiend Technique in Blood Mist Abyss City, it had seemed utterly ordinary, without the slightest distinguishing feature.

That elder had even thought Zheng Yi chose the Black Fiend Technique only to lay a solid foundation before changing to another technique.

But how could he have known that none of these problems existed for Zheng Yi at all?

His goal this time was to refine Azure Profound Fiend.

No one knew what had happened on this athletic field in the past, but its resentment was astonishing. It had formed a Yin Fiend Land, where a hundred ghosts were reborn and the living dared not tread.

Yet to Zheng Yi, it was indeed an excellent place to refine Vengeful Spirits.

Moreover, Zheng Yi had gone on a slaughter spree before. A great number of Vengeful Spirits had already been refined by the Soul Devouring Banner, leaving the place practically swept clean.

The remaining evil ghosts and vengeful spirits were neither numerous nor particularly powerful—just right for him to practice on.

When night fell once more, Zheng Yi set up the Soul Guiding Array again and unfurled the Soul Devouring Banner.

Its thick bronze pole was planted in the ground. Amid gusts of Yin wind, an enormous black banner cloth fluttered up. Dense fiendish aura gathered in, completely shrouding an area dozens of meters wide.

Zheng Yi worked his hand seals and controlled the Soul Devouring Banner, releasing twenty evil ghosts from the black mist.

Led by the Red-Clothed Female Ghost, they concealed themselves within the thick black fog.

"With the Soul Devouring Banner protecting me, cultivating this Black Fiend Technique won't be dangerous."

Zheng Yi was exceedingly cautious. Even here, he retained that same temperament.

It was a habit gradually forged through years of struggling at the bottom of the Cultivation World. In truth, most low-level Rogue Cultivators were like this.

It was not that reckless Rogue Cultivators did not exist, but few of them lived past the Qi Refining Middle Stage.

To ensure he would not be disturbed during cultivation, Zheng Yi chose the safer course and directly released the evil ghosts within the Soul Devouring Banner to guard him. It was time for his magical artifact to do some work.

As expected, the Soul Guiding Array held an incomparable allure for Vengeful Spirits. Even though numerous Vengeful Spirits had all been refined here before, quite a few still roared as they charged into the black mist.

The instant they entered the black fog, the entire Soul Devouring Banner lit up, flickering with a hazy layer of black light. The surging fiendish aura expanded wildly, turning those Vengeful Spirits blind and deaf.

At the same time, the evil ghosts hidden within the black mist suddenly emerged, appearing and vanishing like specters. Under the Red-Clothed Vengeful Spirit's lead, they tore apart the Spirit Bodies of those vengeful spirits and evil ghosts one by one.

Sensing the situation within, Zheng Yi immediately worked his hand seals and controlled the Soul Devouring Banner, opening a passage inside it.

A vengeful spirit whose Spirit Body had been torn apart four or five times and whose vitality had been grievously damaged was sent before Zheng Yi.

Zheng Yi did not stand on ceremony or waste words. In battle, speed was everything. Following the method of circulating the "Black Fiend Technique," he fiercely pressed one hand onto the vengeful spirit's head.

Violent black fiendish aura surged forth like a tentacled octopus baring its fangs and claws.

Terrifying Black Fiend Qi, corrosive to Spirit Bodies, spread out and directly wrapped around the entire vengeful spirit, madly devouring its power.

In about three minutes, that vengeful spirit was completely absorbed.

Everything worked together flawlessly. Under Zheng Yi's control, the Soul Devouring Banner continuously delivered Vengeful Spirits before him, all of them transformed into cultivation resources for the "Black Fiend Technique."

Zheng Yi cultivated faster and faster, his methods growing ever more proficient. By the end, he could almost completely devour a Vengeful Spirit in just over ten minutes.

At the same time, the Black Fiend Qi surging around his body had already transformed into Profound Yin Fiend. Its color resembled black petroleum, gleaming with an inky luster.

Its texture had also changed from its initial gaseous state into a somewhat viscous liquid, gradually shifting toward a peculiar bluish-black hue, though the change was not yet obvious.

If one approached Zheng Yi at this moment, one could clearly feel that the temperature around his body seemed to be gradually dropping.

Within the region shrouded by bluish-black mist, specks of white frost began to form, layer upon layer, congealing without melting.

This was a sign of the technique's advancement. From the initial Black Fiend Qi, it had evolved into Profound Yin Fiend, and was now transforming toward the higher level of Azure Profound Fiend.

With such efficiency, among all Soul Devouring Sect disciples who had cultivated the "Black Fiend Technique" throughout history, there had likely never been anyone before him, nor would there be anyone after.

Even if some Outer Sect Disciples found a Profound Yin Gathering Fiend Land through luck or their family background, they would still need to draw in its power and cultivate slowly. It was absolutely impossible for them to upgrade Black Fiend Qi one level after another so quickly.

Historically, there had been people who, because of cultivating the "Black Fiend Technique," had become deranged murderers, even mutating into Human Demon monsters.

But here, Zheng Yi could kill these Vengeful Spirits without restraint. Not only did he feel no guilt or sin, he was instead doing this world a good deed.

He was helping those who struggled to survive in this world, slightly improving the "harsh" environment.

Cultivators might cultivate immortality, but in truth, they were merely people from the mountains. Killing people and killing monsters were two different matters; it would not damage one's Dao Heart.

The slaughter continued throughout the entire night before Zheng Yi finally stopped.

"I absorbed too frantically during the first half of the month. I've only refined about fifty percent."

Zheng Yi opened his eyes with some dissatisfaction. He casually put away the Soul Devouring Banner, drawing all the released evil ghosts and the Red-Clothed Female Ghost back into it. A helpless expression appeared on his face.

To refine the Soul Devouring Banner, he had directly killed off seven or eight out of every ten Vengeful Spirits in this Ghost School.

In a single night, the Black Fiend Qi of the "Black Fiend Technique" had converted into Profound Yin Fiend Qi, but the transformation into Azure Profound Fiend was only fifty percent complete. It seemed he would have to leave this place.

Then Zheng Yi put away the materials of the Soul Guiding Array and walked out through the school gates. When he turned back to look at the ruined school once more—

A ray of sunlight happened to shine down, golden light blanketing the ruins and bringing with it a warm, comforting feeling.

When he looked again, Zheng Yi faintly felt that this place had become "cleaner."