When the Heavenly Dao Book finished its deduction, Liu Wuxie stood up and began practicing the immortal art. He didn't lack nine elements, but he had to choose which nine to wield. If he chose poorly, the power of the Nine Absolute Fists would drop sharply. After all, many elements countered each other, and the wrong combination might not even compare to an ordinary mythical art.

"Nine elements... I have grasped the five elements as well as the light and dark elements. That makes seven. Which two should I add?" Liu Wuxie murmured as he swiftly mobilized the seven elements.

The five elements could restrain one another, yet they also fuel one another in an endless cycle. Light and dark also mirrored yin and yang, both complementing and opposing each other.

After he refined the Indigo Thunderwood, it added the lightning element to his desolate world, which meant he could draw upon lightning now. The lightning element held terrifying, destructive power, and it would produce an unimaginable effect if he fused it into the Nine Absolute Fists.

That meant he only had to choose the last element. He considered wind and ice, but those two elements felt lacking in pure offensive power. Aside from that, he could also call upon the power of the Buddhist Realm, the Witcher Realm, the Abyssal Realm, and many more. Those forces came from other races, and it remained uncertain whether they could truly merge with the eight elements.

In the end, he chose the Great Poison Mythical Art. The first eight elements already carried overwhelming destructive power, so he didn't need another offensive element. He needed something unexpected, and the Great Poison Mythical Art fit perfectly. Even if he could not kill his opponent outright, he could suppress their immortal energy and disrupt their internal functions by sending poison into their body, creating an opening to finish them off. As for cursed energy or faith energy, those were far harder to deliver as a sneak attack.

As the nine elements came together, they began repelling each other more and more, refusing to harmonize. The fiercest clash erupted between yin and yang. The five elements themselves posed no issue because he had comprehended the Great Five Elemental Immortal Art. However, once the Great Poison Mythical Art joined in, it started eroding the other elements, causing the Nine Absolute Fist's power to sink.

That instantly made things troublesome for Liu Wuxie. With the nine elements clashing, he had to find the perfect point at which they could harmonize, so he tested them again and again, keeping them adjusted as he searched.

After half a day of testing, he finally found the perfect point where everything clicked into place.

"Condense!" Liu Wuxie roared as the nine elements merged, snapped into alignment, and formed nine radiant beams that appeared across the sky. The moment the nine beams appeared, heaven and earth cracked, and Nightmare City trembled violently, while the artifact spirit shook in fear.

Even Liu Wuxie hadn't expected the Nine Absolute Fists to be this powerful. The nine beams quickly coalesced into a devastating punch capable of shattering heaven and earth.

"Go!" Liu Wuxie aimed at the Seven-Fiend Netherworld Chains in the southwest corner to test the power of his fist technique.

As an immortal art from the celestial realm, it made many people in the Indigo Bamboo Astral Domain look up at the sky, unable to comprehend what was happening.

Just moments ago, all the planets had trembled, as it was unprecedented for an immortal art from the celestial realm to appear in the mortal realm. The punch's force condensed into a beam and struck the Seven-Fiend Netherworld Chain.

The Seven-Fiend Netherworld Chain exploded into countless fragments, and Liu Wuxie instantly felt his desolate world drying up. Though it hadn't drained all the immortal energy in his desolate world, it exhausted one-third of it, which startled him.

Based on his current cultivation, he would reach his limit after casting the Nine Absolute Fists twice. When he used the second punch, the immortal energy he required would double, and following that trend, the third punch would demand even more consumption.

The moment the first Seven-Fiend Netherworld Chains snapped, the entire Nightmare City began to sink. The three remaining chains couldn't support the entire city, and the pull yanked several distant mountains.

"I can refine it now!"

Liu Wuxie didn't remove the remaining chains and instead planned to refine Nightmare City first. Once he retrieved the city, he could also take the opportunity to refine the chains.

Countless treasures had forged the Seven-Fiend Netherworld Chains, and he felt confident that letting the Heretic Blade absorb them would upgrade the blade's quality.

Liu Wuxie immediately formed seals, and countless imprints hovered above Nightmare City, fused into the surrounding slabs and buildings, and then burrowed into the city's depths. The artifact spirit resisted at first, unwilling to be refined, and it tried to expel the imprints.

Liu Wuxie snorted. "Hmph, what impudence!"

The artifact spirit had only submitted to survive, and it had never pledged loyalty to him. If the artifact spirit hadn't agreed, it would have been crushed to death by the immortal's will.

However, the moment Liu Wuxie began refining Nightmare City, ripples spread through the deepest reaches of the cosmos, and the one-armed man awakened once more.

"Who is refining Nightmare City?"

This immortal had recovered from most of his injuries, and he could leave his seclusion soon. He had originally planned to retrieve Nightmare City the next month, but someone had beaten him to it.

"Could it be those old monsters from the Skyfall Realm?" the one-armed man murmured. "No, that's impossible! There's still half a month left in the ten-thousand-year cycle. They can't show up now."

According to his calculation, there was still half a month left until the next opening of the Skyfall Realm. So who was refining Nightmare City?

"I won't let you succeed! Nightmare City is only one step away from becoming an immortal artifact, and I even lost an arm to control it. How can I possibly let others seize it?"

The one-armed man's eyes flashed with ferocity as he drew an imprint that shot through space. This was the method of an immortal, and the power was ten times stronger than the will of the Immortal Slaughter Palace's ancestor. Even a quasi-immortal couldn't withstand the power of this imprint.

Just as Liu Wuxie immersed himself in refining Nightmare City, he had no idea an unprecedented crisis was silently approaching.

All of a sudden, the Heavenly Dao Book screamed as a warning about the approaching danger. Liu Wuxie halted what he was doing in an instant and summoned his domain. When the imprint descended from the sky, it turned into the phantom of a one-armed man. It was only a projection, not the immortal's true body.

Astonishment flashed on the one-armed man's face when he saw Liu Wuxie. "A mere cultivator at the fourth-level Heaven Gaze Realm wants to seize Nightmare City?"

He had assumed another immortal was trying to seize Nightmare City, but it turned out to be someone at the fourth-level Heaven Gaze Realm instead.

"Who are you?" Liu Wuxie asked, even though he already had a speculation of the other party's identity. To be able to project a phantom across such a vast distance, he had to be an immortal.

"Brat, I'll give you a chance to submit to me and become my slave. If you do, I will consider sparing your life," the one-armed man said, ignoring what Liu Wuxie said earlier.

"If I'm not mistaken, you're the one who killed the owner of Nightmare City, right? The arm left behind in the underground world was yours, wasn't it?" Liu Wuxie asked, exposing the truth since the other party refused to answer his questions.

The one-armed man narrowed his eyes, and a slight change flickered across his expression. He couldn't understand how Liu Wuxie knew all that.

"I remember now. You're the one who entered the underground world last year and nearly broke the seal to release the artifact spirit, right?" the one-armed man asked, his gaze locked on Liu Wuxie as he recalled the incident that had alarmed him last year.

"That's right," Liu Wuxie replied. Logically speaking, they had clashed once last year.

"Since you know my identity, you should know that I'm an immortal. Kneel!" the one-armed man demanded after examining Liu Wuxie.

"So what if you're an immortal?" Liu Wuxie asked with a mocking expression.

The one-armed man had only reached the first-level Heavenly Immortal Realm, and this was only a projection with combat strength that was not even one-third of his main body's. Even if the immortal had personally come, Liu Wuxie was confident that he could hold his ground.

"You're courting death!" the one-armed man roared in fury. If his main body hadn't been unable to come, he would've already descended in person.

"I advise you to abandon the idea of attacking me. If your projection dies, your physical body will also suffer injuries," Liu Wuxie replied, giving a blatant warning to the other party.

The one-armed man threw his head back and laughed as if he had heard the greatest joke in his lifetime. "Hahaha!"

He found Liu Wuxie amusing because even a quasi-immortal couldn't do anything to his projection.

"Is it really that funny?" Liu Wuxie spoke as the Heretic Blade burst out from its sheath, cleaving down at the projection.

The one-armed man had clearly come to stop him from retrieving Nightmare City. Since there was no room for negotiation between them, Liu Wuxie chose to settle it with strength, but he didn't dare to underestimate the other party, even if it was only a projection.

He had to do everything possible to eliminate future trouble. If he fused the energy of this projection into Nightmare City, it would amplify his refining speed and greatly increase the city's quality.

"What insolence!" the one-armed man roared.

He hadn't struck first, but Liu Wuxie had attacked him instead. In the eyes of an immortal, a cultivator at the Heaven Gaze Realm was nothing more than an ant. How could he not be furious that an ant dared to bite him?

With that, the one-armed man casually slashed through the air, making the sky ripple as the Heretic Blade's attack halted. He displayed the strength befitting of an immortal, and that monstrous power froze the strike with ease.

Seeing the one-armed man dissolve the Heretic Blade's attack with a casual motion, Liu Wuxie immediately raised his guard to the peak. He knew he would die if he weren't careful.

A battle with an immortal would be highly devastating, and the surroundings remained intact only because this was Nightmare City. If this had happened anywhere else, it would have reduced the place to ashes long ago.

How many years had it been since an immortal had last acted in the astral domains? Excluding Liu Wuxie's experience with the Immortal Slaughter Palace's ancestor, the last action from an immortal had dated back three hundred thousand years. Back then, Long Xiao had clashed with the Grand Unity Sect's immortals. The Grand Unity Sect had sent out two immortals and successfully inflicted heavy injuries on Long Xiao.

When the Heretic Blade flew away, Liu Wuxie waved his hand, summoning it back into the desolate world.

"Brat, you might not have a high cultivation, but no ordinary quasi-immortals can rival your combat strength. I didn't imagine that the Indigo Bamboo Astral Domain could produce such a monstrous prodigy like you," the one-armed man said with a hint of surprise across his eyes.

Every era produced prodigies, and anyone who could step into the Immortal Realm was a genius among geniuses. For someone at the fourth-level Heaven Gaze Realm to defeat quasi-immortals, Liu Wuxie had surpassed the level of being a genius and entered the realm of monstrosity.

The fact that the one-armed man judged Liu Wuxie's combat strength at all proved he wasn't ordinary.

"Since that's the case, do you want to keep fighting me?" Liu Wuxie asked. If the one-armed man chose to take a step back, Liu Wuxie had no desire to forge an irreconcilable feud with an immortal.

"Even if your combat strength is great, you're still an ant before an immortal," the one-armed man said coldly. He had only been briefly startled by Liu Wuxie's combat strength, and that moment of surprise didn't mean he feared him.

An immortal would naturally wield immortal arts. Otherwise, it would be pointless even if Liu Wuxie were strong if he didn't grasp any immortal arts.

The one-armed man began forming seals to unleash an immortal art. All cultivators who reached the Immortal Realm could comprehend immortal arts.

"Demonic Blazing Palm!"

The one-armed man struck with a formidable palm technique, unleashing a blazing wave of energy that could roast Liu Wuxie alive.