I'll make you the furnace and the cauldron, so you can refine Yin and Yang and prove the Great

The airship continued to fly below the clouds for more than a month.

During this month, Li Hanshan still didn't waste any time. He cultivated with Yin Lingyue during the day, gradually increasing the strength of his physical body. Each cycle of spiritual energy made his meridian walls thicker and more resilient, and the weak points that had been exposed during the breakthrough to the Void Refinement stage were being strengthened one by one through continuous tempering.

At night, he would drift into a dream and meet Luo Li. The two of them would repeatedly work out the refining method and alternative solutions for the Fusion God Pill on the banks of the Moonlight River, polishing every detail of the incomplete formula to perfection.

They spent the rest of their time cultivating both their spirit and soul, and both of their spirits were constantly improving.

Yin Lingyue's cultivation also improved significantly during this period. Long-term dual cultivation with Li Hanshan made her foundation much more solid than before, and her condition was more than one level better than when she left the Immortal Alliance. The spiritual energy fluctuations flowing around her body had become calm and smooth.

That morning, Yin Yue's voice came from the bow of the ship, breaking the tranquility that had lasted for over a month: "Prepare for landing. We're almost at the Heavenly Demon Sect."

Li Hanshan stepped out of the cabin and stood on the ship's railing. The clouds beneath his feet were much thinner than a month ago, and through the thin mist tinged with a dark gold by the morning light, he could see the vast, desolate land stretching out at the horizon. The mountain ranges were completely different from those of the Immortal Alliance; the ridgelines were more rugged and steeper, like giant beasts crouching on the earth, their backs covered with a very faint layer of dark gray mist covering the primeval forests. The concentration of spiritual energy in the air had clearly increased, yet it carried a strong, chilling quality—the unique aura of demonic energy intertwined with the spiritual energy of heaven and earth.

The airship began its slow descent. Yinyue stood at the bow, her silver veil fluttering gently in the morning breeze.

"She cannot enter the Heavenly Demon Sect." She said, her tone calm but leaving no room for doubt.

Li Hanshan glanced at Yin Lingyue slightly. Yin Lingyue stood beside him, her long, dark purple hair fluttering in the wind. She didn't refute him, nor did she ask why. She simply looked at Li Hanshan, waiting for him to speak.

"Find a secluded spot outside and wait for me," Li Hanshan said to Yin Lingyue. "I'll come find you as soon as I come out."

Yin Lingyue nodded without saying anything more. Having spent so many years in the Yinquan Sect, she was well aware of the strictness of the sect's internal patrols.

If a Nascent Soul cultivator from the Yinquan Sect were to rashly enter the core territory of the Heavenly Demon Sect, and were discovered by the patrolling disciples, there would be no way to explain it, and it would only cause trouble for Li Hanshan.

Yin Lingyue nodded slightly to Li Hanshan, then transformed into a streak of gray-black light and darted out from the side of the flying boat, heading towards the depths of the continuous mountain range below. Her figure was quickly swallowed up by the outline of the dense forest and mountain ridge.

After watching the streak of light disappear into the distance, Yin Yue turned and walked to Li Hanshan. She raised her right hand, and a dark gray aura of spiritual energy appeared in her palm. Fine runes flowed within the aura, resembling a miniature restriction compressed to its limit.

"Before entering the Heavenly Demon Sect, I need to leave something inside your body," she said, her tone calm yet earnest.

Li Hanshan's gaze fell on the dark gray halo: "What is that?"

"The Mark of the Demon Slave." Yin Yue's gaze did not waver. "The Heavenly Demon Sect will verify the identity of all cultivators who enter. You have no demonic aura on you, nor do you have the Heavenly Demon Sect's identity token. If you enter like this, you won't even pass the first inspection. I will plant a Mark of the Demon Slave within you, so that the inspecting disciples will recognize you as my servant. Only then will you be qualified to enter the Heavenly Demon Sect."

Li Hanshan stared at the dark gray halo for a couple of moments before his gaze returned to Yin Yue's face: "You're not trying to take advantage of this to control me, are you?"

Yin Yue tilted her head slightly, a calm indifference, a natural consequence of being questioned, appearing in her serene eyes beneath the silver veil. She didn't rush to explain, but instead took a pure silver jade slip from her sleeve and handed it to him: "This is the method to unseal the seal. Read it yourself and remember it clearly."

Li Hanshan took the jade slip and probed it with his divine sense. The jade slip contained extremely detailed instructions on how to unseal the seal, from the flow of spiritual energy to the order in which the runes were peeled off one by one, and even clearly described what kind of abnormal situation might occur during the unseal process and how to deal with it.

He reviewed the contents in his mind and, after confirming that the method to unseal the seal was indeed complete and effective, handed the jade slip back to her.

"You can unseal it at any time." Yin Yue took the jade slip and put it back in her sleeve. "If you encounter danger during the formation process, you can unseal it and leave at any time. I won't stop you."

Li Hanshan remained silent for a moment. He weighed the matter in his mind. The Demon Slave Mark might be a heavy shackle for others, but Yin Yue had proactively told him the method to remove it, and there was also a Heavenly Oath between them. If she truly wanted to control him with this mark, she wouldn't have needed to go to such lengths.

In addition, his pure yang fire is the nemesis of these demonic marks. At worst, he can use the pure yang fire to burn himself inside and out, which is enough to burn any mark completely.

Although, that process was somewhat painful.

He nodded. "Okay. Let's go."

Yin Yue said nothing more. She raised her hand and pressed the dark gray aura of spiritual energy towards Li Hanshan's brow. The moment the aura touched his skin, an extremely cold spiritual energy seeped into the edge of his sea of ​​consciousness from the point of contact, slowly coiling around the outermost layer of his sea of ​​consciousness like a dark gray, cold snake. That spiritual energy condensed into a dark mark as thin as a hair at the edge of his sea of ​​consciousness, its overall structure more refined and concealed than the Heavenly Demon Mark she had seen on He Yuan.

The moment the mark took shape, Li Hanshan could feel the warm aura naturally emanating from the pure yang energy on the surface of his body being suppressed by some force. From the outside, it looked as if he was enveloped by a very faint, cold aura, no different from the aura of an ordinary demonic cultivator.

He tried to touch the edge of the mark with pure yang energy; the touch felt like a thin, smooth, and intact film of ice. However, he was certain that the mark's foundation was not deep; with a gentle touch using the techniques of the seal-breaking method, he could peel it off entirely.

"That's enough." Yin Yue withdrew her hand, her gaze sweeping over the spiritual energy fluctuations around him. After confirming that the Demon Slave Mark had completely merged with his aura, she nodded slightly.

She turned and walked back to the bow of the ship, activated the array base, and the flying boat sped towards the depths of the mountain range shrouded in demonic energy below.

As the flying boat passed through the dark gray mist, Li Hanshan could feel the concentration of demonic energy in the air rapidly increasing. That chilling aura surged from all directions, blocked by the protective shield on the flying boat's surface, yet still managed to seep in through the gaps in the array patterns, causing his pure Yang meridians to tense slightly for a moment. He looked at the rapidly expanding mountain range ahead, and his assessment of the Heavenly Demon Sect's overall strength was being recalibrated.

The airship flew at low altitude for more than half a month. The route chosen by Yinyue followed the contours of the mountain ridges, occasionally skirting the sides of mountain peaks and silently passing through the shadows of the mountains.

During this period, Li Hanshan observed the distribution of spiritual energy along the way almost every day—the sect strongholds scattered among the mountains, the patrol routes, and the direction of the earth vein spiritual energy were all recorded in the depths of his sea of ​​consciousness.

After flying for another half month, Yin Yue's flying boat began to slow down.

Standing at the ship's railing, Li Hanshan's first sensation was the change in the sky. The previously clear sky rapidly darkened at the edge of his vision, not in the way obscured by clouds, but in an extremely intense dark red that slowly spread across the void. This dark red, like a layer of shattered blood-red paint, covered the entire sky, with fine, dark golden arcs of electricity surging at its edges, dyeing the sky for thousands of miles around a oppressive and heavy dark red.

The flying boat came to a stop beneath the dark red sky. Yin Yue stood at the bow, her silver veil fluttering gently in the oncoming demonic wind, her voice coming from ahead: "That is the Heavenly Demon Blood Array."

Li Hanshan's divine sense spread out. The moment he sensed the formation, his pupils contracted slightly. The entire Heavenly Demon Blood Formation covered an area of ​​several thousand miles, like a dark red dome stretched to its limit, enveloping all the mountains, valleys, and palace complexes of the Heavenly Demon Sect.

Tens of thousands of dark red runes flowed across the surface of the dome. The runes were arranged with extreme precision and were connected to each other by dark golden spiritual energy threads, like a giant net that had been repeatedly woven over thousands of years.

He could sense that the runes contained extremely dense demonic energy and earth vein spiritual power. The entire formation perfectly aligned with the earth veins below, drawing in, guiding, and compressing the spiritual power deep within the earth veins layer by layer, ultimately injecting it into every node of the formation, forming a perpetually circulating spiritual power barrier. Its structure was more robust than the Flowing Light Formation, and not as refined, but it excelled in its massive size and abundant spiritual power reserves.

"As expected of the sect's protective formation, even if there are no Dao Integration Realm cultivators guarding it, a few Dao Integration Realm cultivators wouldn't be able to break through it in a short time," Li Hanshan said.