Nie Kong’s heart jolted. The mass of dark green blood within him had been stagnant for ages, and this sudden fluctuation—what could be the reason?

As the blood began to ripple like disturbed water, the Purple Phantom Spirit Incense floating atop it trembled precariously. Thankfully, the little creature, still in its slumber, absolutely would not awaken before truly advancing to the Fourth Tier; otherwise, it would have given Nie Kong yet another headache.

Backing away several steps against the current, the mass of dark green blood gradually calmed down!

Nie Kong suddenly realized that somewhere upstream in this cold current, there had to be something attracting it, much like Long Xuechan and that formless spiritual energy. He recalled that when he carried Long Xuechan’s colorless spiritual energy within him, the energy would rebel the moment he got close to her.

Understanding this, Nie Kong’s excitement soared. His Half-Spirit lineage originated from the Yin Ruins; therefore, only something from the Yin Ruins could possibly be attracting this essence. Hadn’t he come to Lingyu City, single-mindedly aiming to become an inner disciple, just to gain entry into the Yin Ruins?

If he could locate something upstream in the cold current capable of attracting the dark green blood, it might greatly benefit his long-term plans. With this thought, Nie Kong quieted his turbulent mind, stabilized his body, which was slightly swaying from the current, and began moving step-by-step against the flow.

He surfaced twice mid-journey to catch his breath. Nie Kong was drawing nearer to the steep slope ahead, and the fluctuations within the dark green blood grew increasingly intense.

Simultaneously changing were the force of the current and the pressure cascading down from above. Nie Kong found movement arduous, his body forced lower and lower.

Finally, between two stones forming a narrow fissure, a small cluster of dark green luminescence entered Nie Kong’s sight.

"That’s it!"

Nie Kong rejoiced inwardly.

At that moment, the dark green blood in his Yaochi Acupoint began to boil fiercely, like water brought to a rolling boil, tossing the Purple Phantom Spirit Incense, currently curled into a seed shape, back and forth, as if it might burst through the seams of the ‘Four Spiritual Apertures’ at any second and reintegrate into his entire circulatory system.

After struggling to hold on for over ten seconds, Nie Kong thrust out his arm, plunging his fingers into the gap between the two stones with lightning speed.

"Hah! The instant the mass of dark green light entered his grasp, a powerful surge washed over him. Nie Kong could no longer keep his footing, tumbling backward with the flow. But Nie Kong remained calm, constantly adjusting his posture to navigate the current, ensuring he never strayed outside the encompassing glow of that faint green light at the river's center.

Washed back dozens of meters by the rush, Nie Kong barely managed to regain his balance.

In an area where the current softened, Nie Kong peered closely, realizing what he held was a dark green stone, about three fingers wide, perfectly smooth and crystalline. Merely holding it in his palm transmitted a dense, strange aura radiating from the small round stone, seeming intent on swallowing Nie Kong whole.

"Whoa! In the Yaochi Acupoint, the dark green blood surged high, violently forcing the Purple Phantom Spirit Incense floating above it down to the very bottom of the Hidden Aperture. Nie Kong’s heart skipped a beat. He quickly calmed his focus, concentrating his attention on the dark green stone in his palm. A moment later, he swiftly tucked it into his Pet Backpack.

Without that dark green stone, the blood in the Yaochi Acupoint quickly subsided. In less than ten seconds, all movement ceased, and the little creature floated serenely once more.

What a bizarre aura!

Nie Kong impatiently longed to examine the stone thoroughly. He immediately surfaced and saw Bai Yuqing seated quietly on the riverbank, her beautiful eyes rapidly scanning the water’s surface. He waved his arm vigorously at her, instantly drawing her gaze, and silently conveyed: Meet me at the pavilion residence in about half an hour.

After coaxing the two newly awakened little girls, Long Yan and Long Ting, to go to the thirty-third floor to find Miao Ge and Tai Ji, Nie Kong hurriedly took out the small round stone.

The dark green blood began to boil again.

"Hum!" With a deep, dull resonance, the slender Heavenly Array needle he had prepared plunged into his lower abdomen.

A sharp burst of emerald light flashed. Dense spiritual markings on the needle’s body exploded into brilliant light, and the sharp tip simultaneously vibrated violently within the Yaochi Acupoint. In an instant, the Yaochi Acupoint was completely sealed by the golden needle; no matter how much the dark green blood surged, it could not escape its confines.

While continuing to manipulate the Heavenly Needle with his right hand, Nie Kong held the round stone in his left, examining it closely.

Only then did Nie Kong discover that the surface of the perfectly smooth, round stone was covered in countless tiny holes, as fine as human hair, like skin. Veins of faint dark green luminescence seeped out from these dense pores, giving the entire stone its characteristic dark green hue.

"The blood is dark green, and the stone is dark green," Nie Kong mumbled to himself. After a moment of silence, he carefully channeled a weak wisp of spiritual power into the small dark green stone.

"Boom! A violent tremor erupted. The dark green light radiating from the stone abruptly intensified several times, forcing Nie Kong to squint involuntarily.

At that moment, the faint, thread-like spiritual power vanished as if a clay ox had entered the sea.

Almost simultaneously, a strange aura, like a spiritual snake, drilled into Nie Kong’s palm, and then, as if guided by instinct, traveled up his arm to hover just outside his Yaochi Acupoint.

"What is this?"

Nie Kong’s heart lurched. He abruptly flipped his hand, intending to release the dark green stone, but it adhered to his palm like a suction cup. The bizarre aura poured continuously out of the stone, entering his palm, and then all of it gathered around the Yaochi Acupoint.

Had he messed up?

Frowning slightly, Nie Kong willed his Apertures to shake violently, sending a massive surge of spiritual power down his left arm, which instantly burst forth from his palm. Yet, the stone showed no sign of detaching, clinging tightly to his palm, and the strange aura emanating from it grew ever stronger.

It seems the stone won’t let go until it's entirely absorbed!

Nie Kong felt a severe headache coming on. He had hoped to uncover secrets related to the Yin Ruins here, but instead of finding secrets, he had created a pile of trouble.

The strange dark green auras massed around the Yaochi Acupoint, restless and eager. The moment Nie Kong lifted the seal on the Hidden Aperture, they would undoubtedly swarm inside.

Moreover, if the dark green stone was too firmly attached to be dislodged by spiritual power, then the dark green auras surrounding the Yaochi Acupoint would undoubtedly be impossible to expel from his body, just like that initial mass of blood.

"Rather than let them rush in, I’ll let them enter bit by bit!"

Nie Kong secretly gritted his teeth and instantly made his decision. The speed at which his right hand manipulated the needle became erratic—sometimes fast, sometimes slow—causing slight gaps to appear in the Yaochi Acupoint sealed by the Heavenly Needle. The dark green auras, which had been wildly colliding around like headless flies, seemed to have found an exit and frantically squeezed toward the opening.

As if sensing the entry of the dark green auras, the blood in the Yaochi Acupoint became even more 'agitated,' surging toward the gap.

In an instant, that thread of dark green aura was swallowed by the rising blood...

Nie Kong’s thoughts spun rapidly. He widened the gap in the Yaochi Acupoint further, allowing more dark green auras to pour in. To Nie Kong's surprise, as the absorbed dark green auras increased, the mass of blood gradually grew calmer, simply consuming the surging auras relentlessly...

"Dong!" A reverberating sound suddenly echoed.

The dark green round stone finally detached from Nie Kong’s left palm and fell to the ground. At that moment, the stone, which had been faintly glowing, turned dim and lusterless. Its smooth, polished surface now revealed dense indentations, each the size of a soybean speck. From a distance, it resembled a piece of honeycomb.

"Ha!" Nie Kong let out a soft breath and slowly withdrew the Heavenly Needle. The instant the stone hit the floor, all the dark green auras surrounding the Yaochi Acupoint had been completely absorbed by the mass of blood.

Clearing his mind, Nie Kong observed carefully...

The dark green blood did not expand as it had after treating Nie Shen Gong previously. Despite absorbing all the dark green energy, the blood showed no numerical change, yet Nie Kong could sense that the power implicitly contained within it had grown stronger.

Retrieving the Heavenly Needle into the Pet Backpack, Nie Kong stood up and paced back and forth in the chamber. "The dark green blood in my body has increased its power by absorbing the strange essence from that dark green stone. If that’s the case, perhaps that essence acts as nourishment?"

"Nourishment for the Half-Spirit bloodline?"

Nie Kong murmured to himself. Since the Half-Spirit lineage originated from the Yin Ruins, its nourishment should also come from the Yin Ruins. But this appeared in the cold current of the Senluo Ancient Cave—"Could it be that the cold current also originates from the Yin Ruins?"

Suddenly, a bold hypothesis flashed through Nie Kong’s mind.

If that river truly flowed from the Yin Ruins, wouldn't following it upstream lead directly to the Yin Ruins described by Hua Yanji?

The thought made Nie Kong uncontrollably excited; he desperately wanted to return to the Senluo Ancient Cave immediately and investigate the cold current. However, just as his foot reached the doorway, Nie Kong suppressed the impulse in his heart and returned to sit quietly on the chair.

Reflecting on it, Nie Kong realized his idea was too wishful.

How vast was the Tianling Continent? Although the essence in that dark green stone could serve as nourishment for the Half-Spirit bloodline, such a peculiar thing wasn't necessarily exclusive to the Yin Ruins. Furthermore, since Lingyu City held some connection to the Yin Ruins, it was possible that Lingyu City itself possessed such items, which then accidentally fell into that hidden current due to some mishap. While the probability was low, it wasn't impossible.

The crucial point was that Nie Kong's current cultivation level was insufficient. Even if that cold current truly led to the Yin Ruins, he couldn't arrive safely with his current strength.

After all, the exposed portion of the cold current deep within the Senluo Ancient Cave was only about a thousand meters long. Not far past the steep slope upstream was a gloomy stone cavern, unlike the section in the ancient cave where both banks provided resting spots. Moreover, Nie Kong had no idea how long that inner cavern extended. Lingering for too long in such an environment, even if he avoided freezing to death, he would suffocate.

"It won't be too late to investigate once I reach the Spirit Transformation stage. The most crucial thing now is to enhance my cultivation!"

Nie Kong silently resolved this internally. Just as he bent down to pick up the stone, which had turned completely dark, the Purple Phantom Spirit Incense, curled into a seed shape in his Yaochi Acupoint, suddenly unfurled—"Tinkle, tinkle, tinkle..."

A series of clear, pleasant chimes echoed in Nie Kong's mind...? Third watch complete...