What surprised Nie Kong even more was that after reaching great spiritual accomplishment, the "Prison Fire Dark Spring" could actually change its form at will. In the span of just half a minute, her countenance morphed from Qing Yue to Nie Kong, then from Nie Kong to Pan Hu, before finally returning to Qing Yue's exquisite visage.

Seeing the water spirit so pliable, Qing Yue’s eyes turned red with envy. Although her current strength surpassed the "Prison Fire Dark Spring," her essence was a second condensation, fixed and unchangeable—no comparison to the "Prison Fire Dark Spring" at all.

What offered Qing Yue a sliver of comfort was that the current "Prison Fire Dark Spring" had a mouth and feet, yet it could not speak, only emitting watery gurgles to express its emotions. It couldn't walk or stand either, merely flowing here and there like water.

“This little thing needs a lot of *** training. It seems Grandma is going to have plenty to keep her busy,” Qing Yue mused, stroking her chin, grinning like a fox who had just successfully pilfered a chicken. She then squinted at the "Prison Fire Dark Spring," constantly beckoning, “Little Youyou, good girl, come to Grandma…”

“……”

It was unclear what method Qing Yue used, but she soon coaxed the "Prison Fire Dark Spring" away from Nie Kong's shoulder. Moreover, she gave it a name: "Qing You." Not only did the "Prison Fire Dark Spring" not object, it appeared incredibly delighted.

Watching Qing Yue attempt to teach Qing You how to walk in the distance, Nie Kong couldn't help but chuckle.

“For a spiritual treasure of such nature, for an ordinary person to acquire even one is a blessing rarely seen in a century. Yet you have obtained two—truly an exceptional fortune,” Pan Hu’s figure appeared silently beside Nie Kong, saying this with a face full of smiles.

Nie Kong nodded in agreement, then suddenly asked, “Senior Pan Hu, now that the water spirit has awakened, can we proceed to the fifth benefit?”

“You little fellow, you’re truly afraid this old man will default on his promise.”

Pan Hu couldn't help but smile. “Since you are so eager, then I won't waste any more time. Others believe the place within the Underworld Sea with the densest dark spiritual element is the Fire Source above. That is incorrect; the densest concentration should be the 'Spirit Marrow' within my body. This Spirit Marrow is the root source that allows me, along with Chi Lian and other 'Supreme Spirit Realm' Star Gods, to continue nurturing 'Underworld Origin' even after death.”

“Spirit Marrow?”

Nie Kong’s heart stirred.

“Come with me.”

Pan Hu smiled and drifted to the right, his body moving like a phantom. Nie Kong glanced at the lingering Qing Yue and Qing You, then flashed his figure and followed. A moment later, the two little ones also tumbled through the air with a whoosh, quickly trailing behind.

Soon, Nie Kong understood that Pan Hu was heading toward the brain region of his body.

Passing through the straight space of the neck, Pan Hu and Nie Kong appeared one after another within the spherical space of the brain. Deep within this area, there was a small pool, several meters square, filled with inky black, viscous liquid, much like the Underworld Sea outside.

“This is my 'Spirit Marrow,'”

Pan Hu stopped, pointing to the pool, and chuckled, “This pool of Spirit Marrow is a microcosm of the entire Underworld Sea. Previously, when you cultivated outside, you needed a constant process of circulation, absorption, and refinement. If you cultivate within this Spirit Marrow, the dark spiritual elements will enter your body on their own, saving you the absorption process; you only need to refine them. Furthermore, the speed of refinement will far surpass cultivating outside.”

Speaking of this, Pan Hu also showed considerable emotion. “Of course, this place is very important to me. It is only because your body is suitable for my heart to possess, allowing me to contend with that woman, Da Yan, that I permit this. Otherwise, even if you were Chi Lian’s disciple, I would grant you at most the first four benefits, but not allow you to cultivate in this 'Spirit Marrow.' However, with my current abilities, I can only support the advancement of your main body and your avatar by one realm each here. Allowing you to cultivate further would be too much for me to bear.”

“Understood,”

Nie Kong said solemnly, “As soon as my cultivation reaches the required level, I will immediately exit the 'Spirit Marrow.'”

“Very good, then cultivate well. I also need to make proper preparations for what comes next.” Nodding with satisfaction, Pan Hu’s figure warped momentarily, instantly transforming into a streak of blood-red light, shooting toward the chest space ahead.

“Qing Yue, take good care of Qing You.”

Nie Kong patted Qing Yue’s small head and stepped into the pool. Just like in the Underworld Sea, Nie Kong’s body rested on the surface without sinking.

“Hoo—”

In an instant, it was as if a hurricane swept through the pool, causing the water surface to churn violently. Without Nie Kong needing to circulate any spiritual techniques, dense inky-black energy surged up from the Spirit Marrow, thickly enveloping Nie Kong and drilling frantically into his body.

In the blink of an eye, Nie Kong’s figure was submerged in blackness.

When he was outside the pool, Nie Kong hadn't felt much, but now, immersed within, the feeling of the rich death qi drilling into him from all directions was overwhelming. Caught off guard, Nie Kong was almost choked into suffocation by the impact of this death qi. How could cultivation speed not be fast in such a place?

Now, Nie Kong completely believed what Pan Hu had said earlier: where the sects of the Underworld Earth were located, there was a Spirit Marrow, large or small, and only in such places could Underworld Origin be born, giving rise to regions suitable for Black Spirit Masters to cultivate.

With a thought, Nie Kong hastily activated the "War God Star Seal" and the "Yin-Yang Spirit Devouring Art."

“Hoo—”

Suddenly, it was as if a bucket of gasoline had been dumped onto a blazing fire. More and more death qi rose from the Spirit Marrow, forming a massive, inky-black vortex above the pool, surging into Nie Kong’s body at an even faster rate, like an overwhelming tidal wave.

Nie Kong dared not be distracted any longer. He quickly calmed his mind, continuously separating the death qi that automatically rushed into his body, refining it within his main body and avatar separately. Just as Pan Hu had mentioned, cultivating in this Spirit Marrow was indeed much more convenient; not only was absorption unnecessary, but unlike in the "Heart of Flames," he didn't need to pass the scorching energy through a seed and expel it from his body.

For a time, the death qi within Nie Kong’s main body and the spiritual power of his avatar both surged as if injected with adrenaline, increasing in intensity madly…

“This is too terrifying, isn’t it?”

Sensing the aura spreading from the pool, Qing Yue’s large eyes widened. Previously, the Spirit Marrow had been calm, yielding no sensation, but now that it was fluctuating, how could she, who had recovered her cultivation, fail to notice the sheer density of the death qi within the pool?

After a while, Qing Yue snapped back to her senses and couldn't help muttering, “If he could cultivate in a place like this constantly, this little fellow Nie Kong would probably only need a few years to become a Heaven Spirit Master?”

“Splash—”

Qing You blinked her watery eyes and nodded in agreement.

“I’ve told you several times, you can’t agree with people by saying ‘splash.’ You must say ‘En,’ ‘Yes,’ or ‘Correct’… Oh dear, why are you lying down again? You are a person now, you have to stand up to talk like people do!”

Qing Yue glared, waving her little hands, and dragged Qing You, who was lying flat with her head held high, up from the ground.

When Qing Yue released her grip, Qing You managed to maintain a standing posture, but her soft body swayed side to side like a noodle, seemingly about to collapse at any moment. Qing Yue swung her small fists, cheering on the "Prison Fire Dark Spring" beside her.

After a long time, Qing You's body finally stabilized, only her legs trembling violently. Qing Yue wiped her forehead, letting out a breath of relief, and earnestly instructed, “Little Youyou, you must stand like this from now on, understand?”

“Splash…”

Qing You uttered a sound, but upon seeing Qing Yue’s fierce glare, her body instantly went limp, and she flopped back onto the ground, nodding repeatedly: “En, correct, En, correct…”

As she spoke, Qing Yue squeezed out a smile, but the smile wasn't on her cheeks—it was on her nose, making the expression look incredibly bizarre.

“It’s over, all that teaching was useless,”

Qing Yue nearly spat blood, tumbling onto the ground, humming weakly, “Grandma’s fate is truly bitter. I finally get to be a teacher, and I run into such a dull student… Eh? Didn’t she reach great spiritual accomplishment? Why can’t she learn after so many tries?”

Qing Yue glanced over and saw Qing You grinning, clutching her stomach, her shoulders trembling continuously, seemingly suppressing a laugh. Noticing her gaze, Qing You quickly calmed her body, her eyes showing a confused expression. However, Qing Yue had already jumped up and firmly straddled Qing You’s back.

“Little Youyou, you are truly naughty, not good at all! How dare you tease Grandma! Hmph, you are done for! Do you think Grandma is so easily teased?”

Qing Yue roared like an enraged little lioness, her voice echoing in the brain space of Pan Hu’s body…

…

Just as Qing Yue was angrily *** the "Prison Fire Dark Spring," the vortex storm in the pool intensified slightly. At this moment, the entire Underworld Sea outside began to convulse. Waves tens of meters high were continuously hurled into the air, one after another, as if the apocalypse had descended.

The black energy filling the void also surged, forming a gigantic vortex above the Underworld Sea, spinning madly. The Underworld Beasts beneath the seabed also seemed powerfully affected, their roars and howls, varied and continuous, rising incessantly.

The Black Spirit Masters who were long stationed by the Underworld Sea shore observing the situation were terrified and dumbfounded by the sudden frenzy of this sea area. After a long pause, they all startled awake and frantically used their "Golden Armor Jade Slips" to transmit the news back to their sects.

…

War God Mountain.

Inside the War Heart Hall, the Clan Leader Zhan Yunlan, the Supreme Elder, and the Elders were gathered, discussing the news Zhan Yunlan had brought back from the "Sect Alliance Conference."

The time for clearing the Ghost Domain was fast approaching this year. At that time, all Super-Tier and High-Tier sects would be required to send personnel into the Ghost Domain to hunt the Underworld Beasts within.

For the Black Spirit Masters of the Underworld Earth, the Underworld Beasts in the Ghost Domain were like leeks—once harvested, they quickly grew back, requiring another harvest. Otherwise, if the beasts inside became too numerous, they would break through the seal at the passage entrance and rampage across the Underworld Earth.

For nearly a thousand years, it was precisely through proactively slaughtering the Underworld Beasts that the seal remained intact, ensuring the people of the Underworld Earth no longer feared sudden attacks from these beasts. However, clearing the Ghost Domain was extremely perilous, making the selection of personnel sent there a matter of utmost importance for every sect.

…