Outside of Meng Fortress, the five great demon kings were still in the middle of attacking Xiang Yu, sending his bones and flesh flying everywhere, nearly making him lose his shape as a human. It was especially true for Jin Jia and Xiong Wanling, as both of them were extremely ruthless and violent. They did not like to attack their enemy with Dharma spells, but instead, they resorted to pure violence. With every punch and every kick they thrust, blood splashed, and gore was sent flying. It was a ghastly scene to look at.
Meanwhile, the pinkish flying sword of Su Mei'er, and the crane beak of He Qianqiu, both kept piercing through Xiang Yu's body, breaking his bones and taking away bits and pieces of it.
However, the one that inflicted the most damage to Xiang Yu was undoubtedly Huo Wuyu's Rotting Bones and Soul Devouring Energy. Not only would the foul and vicious soul devouring energy melt down Xiang Yu's muscles and bones, it was also crazily corroding his Nascent Divinity. Through the Mystic Eyes of Universe, Wu Qi saw Xiang Yu's Nascent Divinity was putting up a desperate struggle against the invasion from the blood-red shadow of celestial fiend behind his back, and the fierce corrosive force of the soul-devouring energy. Facing both the attacks at the same time, Xiang Yu's Nascent Divinity was like a weak candle flame amidst a fierce gust of wind, facing the risk of dying off at any time.
Once his Nascent Divinity was wiped out, everything would vanish into nothingness.
Wu Qi looked at Xiang Yu coldly, who had lost his ability to fight back under the siege from five great demon kings. Suddenly, he waved his left arm and activated the Earth Element Dragon Scales Shield. Immediately, several tens of thousands of dragon-scales-shaped golden beams, shrouded in earthy yellow mist, shot straight towards Xiang Yu while generating muffled wind breaking noises. Each of these golden beams weighed over several hundred thousands of kilograms. As they traveled at the speed a few time faster than the speed of sound, the forces carried by them allowed them to easily pierce through several dozens of lofty mountains.
Like a raging rainstorm, countless golden beams shot out whistling, piercing through the Rotting Bones and Soul Devouring Energy and smashing aggressively into Xiang Yu's body. His pale dark bones were being heavily impacted by these golden beams, cracking and breaking from their tremendous weight and incredible speed. Then, these golden beams flew back and forth around Xiang Yu, smashing and slamming at him repeatedly. They took away the last bits of skin and flesh from his bones, and chipped away his bones layer by layer.
Deep, muffled noises of impact kept echoing out. Very soon, Xiang Yu was left with just his skull, shrouded in a blood red energy barrier, while all the other parts of his body were smashed and shredded into a mess.
All five demon kings were taken aback by Wu Qi. As they had been crazily attacking Xiang Yu for some while, they knew how tough his body was, as they were only able to rip and tear apart his flesh and bones relying on their mighty strength and the power of upper-grade magical treasures. The fact that Wu Qi's Earth Element Dragon Scales Shield was able to cause damages to Xiang Yu's fleshly body proved that this magical treasure had incredible power.
All of them gave Wu Qi a look nearly at the same time. As the golden beams had the shape of dragon scale and a very obvious aura of flood dragon, they knew their origin. Meanwhile, they nodded their heads slowly when they saw the dense and heavy, earthy yellow mist shrouding the golden beams, as they knew Wu Qi had purchased a clump of Innate Earth Element Energy Essence in the Rare Treasures Conference. However, it was out of their expectation that Wu Qi had already crafted it into a defensive magical treasure in such a short time.
"What a lucky kid!" Huo Wuyu took a deep break, then gave a long screech, spraying out another ball of soul-devouring energy. Amidst the pale green soul devouring energy, the golden beams that shot out from the Earth Element Dragon Scale Shield continued flying back and forth. As the dragon scales were protected by that Innate Earth Element Energy Essence, they could ignore the frightening corrosive force of the energies. Huo Wuyu's face turned unsightly. To him, this was evidence that this defensive magical treasure could withstand his strongest innate ability.
The group continued their attack on Xiang Yu's remaining skull. Sparks were flying everywhere, and the blood-red energy barrier was flashing and blinking. As the Banner of Chiyou had transformed into a dense and thick layer of blood-red energy barrier that was wrapping around this skull, no matter how hard they attacked, there was no way they could break the strong defense put up by it. Regardless it was Wu Qi or the five demon kings, none of them had the murderous aura and the virtue of Human Emperor, which was used by the Human Emperor Xuan Yuan when he killed Chiyou. They were the only bane of the Banner of Chiyou, and it was impossible for Wu Qi and the five demon kings to possess such a mighty aura.
Yan Dan frowned as he looked at Xiang Yu's skull protected by the Banner of Chiyou. The aura of life and death was rolling violently about him, yet he too had no better idea in dealing with the Banner of Chiyou. As he was cultivating the Reincarnation Technique of Nine-death and Nine-resurrection, it was not a technique that could do too much of harm to the Banner of Chiyou. To be frank, it was indeed that Yan Dan's aura of Human Emperor was weaker than Ying Zheng, let alone compared to the legendary Human Emperor, Xuan Yuan.
The Banner of Chiyou had completely wrapped around Xiang Yu's skull, channeling dense and strong blood-red murderous aura into it. At the same time, the blood-red shadow of the celestial fiend behind Xiang Yu was twisting and moving rapidly, crazily invading Xiang Yu's Nascent Divinity. Together with the attack from Rotting Bones and Soul Devouring Energy, Xiang Yu's Nascent Divinity could no longer endure the joint attacks from the three parties. Abruptly, his Nascent Divinity disintegrated, transforming into a sheet of blinding blood-red gleam, and burst out from all seven apertures of his skull.
"You've pushed me too far!" Xiang Yu's voice was heard coming from the ferocious looking skull.
"Yuji, oh Yuji, I've waited for you over two thousand years, and yet, this is the way you chose to treat me?" Xiang Yu howled shrilly in sadness, "In that case, I'll give away my mortal status and become a fiend. I’ll transform myself into a true body of a celestial fiend, ditch away all feelings of an ordinary mortal, the benevolence, the compassion, the tenderness, and the kindness, to truly become the War Fiend of the ancient time - Chiyou! And I will fight among all of you for the throne, to see who will be the true lord of this Heaven and Earth, who will be the number one hero under the heaven!"
Very quickly, the blood-red shadow of celestial fiend behind him fused with his skull.
At the same time, the Banner of Chiyou transformed into a sheet of glittering light and fused with his skull as well.
With that, Xiang Yu's Nascent Divinity was reborn in his Spiritual Ocean. It was a vague shadow that was formed with countless streams of sticky blood. Although the figure was still vague and rather incorporeal, as if it had yet to take a complete form, it had already emanating a vast flame of fiendish and murderous aura. Gradually, wave after wave of frightful aura spread out from the skull, making one's blood boil. One could hardly contain the desire of picking up a weapon and engaging in a deadly slaughter.
Princess Zhang Le's face fell suddenly.
Xiang Yu's skull opened its mouth and gave a ferocious laugh, as his voice echoed out, "How dare a little girl like you try to trap me using a spirit sealing spell? Break!"
Following Xiang Yu's shout, a tiny blood-red speck flashed in the air, then a fine wisp of blood-red flame emerged. Following a faint thread of connection between Princess Zhang Le's soul and the spell of divine seal she cast previously, it quickly shot towards her. Her spell was completely removed, while she coughed up a mouthful of blood as a tremendous backlash hit her. The blood-red flame smelled her blood and increased its speed towards her.
Without hesitation, Wu Qi waved his hand, transforming the Earth Element Dragon Scales Shield into a layer of heavy and thick, yellow energy barrier, enveloping him and Princess Zhang Le within. Then, all thirty-six thousand dragon scales shot out, orbiting around them according to the path of all the stars in the universe. In the next moment, the blood-red flame approached them at top speed while bringing together loud roaring and yelling of foul souls, then viciously smashed onto the dragon scales and yellow energy barrier. A loud boom rang out. The blood-red flame exploded, sending out a tremendous murderous force, knocking Wu Qi and Princess Zhang Le away, tumbling back into Meng Fortress, crashing several dozens of tall towers along the way and finally smashing onto the ground.
Fortunately, as both of them were protected by the Earth Element Dragon Scales Shield, they only suffered a great shock, but no injury.
Wu Qi cupped Princess Zhang Le with his arms and sprung up, then gave a loud shout, "All the cultivators in Meng Fortress, listen to my command! Attack Xiang Yu with lightning technique! I want to see exactly if this Xiang Yu does truly cannot be smashed and killed!"
The cultivators of Xiantian realm could not lock down the hundred miles away Xiang Yu with their divine sense, but Human Immortals of Gold Core realm and Earth Immortals of Nascent Soul realm could always attack their enemies from such a distance using Dharma spells and divine abilities. Wu Qi had given out his command with the title of deputy chief supervisor of West Field Headquarter, and immediately, among all cultivators in Meng Fortress, about twenty Nascent Soul cultivators and one hundred Gold Core cultivators quickly locked down Xiang Yu with their divine senses. They then began throwing out various talismans and spells that poured towards Xiang Yu like a raging rainstorm.
Numerous lightning bolts mixed with the Rotting Bones and Soul Devouring Energy and hit Xiang Yu's skull, exploding and causing the blood-red energy shield to flash and blink endlessly. Abruptly, the Banner of Chiyou burst out with a towering fiend flame, enveloped Xiang Yu's skull, and fled towards the depth of Meng Mountains, leaving behind a long blood-red beam in the air and the loud roars of Xiang Yu.
The surrounding natural energies had once again rushed towards Xiang Yu crazily, fusing into his skull. Tiny threads of flesh and skin began quickly grown out on his skull, then strands of blood-red hair began poking out from the fresh scalp, extending very quickly and soon turning into a head of ten feet long, blood-red hair. After that, sounds of cracking echoed rapidly, as a fresh, pale black, and half-transparent backbone stretched out from under his skull. With this backbone as the core, his rib bones, pelvic bone, and all other bones kept growing out. In just a few breaths, the entire skeleton of Xiang Ta had completed its rebirth.
Shockingly, this newly born skeleton of Xiang Yu was at least ten times stronger than his previous bones! When Xiong Wanling's bear palm, Jin Jia's huge hammer, Su Mei'er's flying sword, and He Qianqiu's crane beak landed on his body, they could only generate a massive amount of sparks, leaving behind deep marks, but failed to crack and smash any of his bones anymore. On top of that, when the lightning bolts fell and hit on him, they only left a thin layer of faint lightning on the surface, and could not break through his defense.
Even when the most vicious Rotting Bones and Soul Devouring Energy sprayed and sprinkled on Xiang Yu's bones, they could only make the blood-red energy barrier ripple, and could no longer inflict any damage to Xiang Yu. Together with a strong blood-red light, the Banner of Chiyou shot out from Xiang Yu's head, gradually spreading and extending the blood-red energy barrier. It pushed and blocked Huo Wuyu's soul-devouring energy from getting any nearer to Xiang Yu.
Xiang Yu had given up something that he held firmly in his Nascent Divinity, and chose to merge completely with the soul of celestial fiend that was cultivated by him. With that, his body was now slowly transforming into a true fiend body of immortality. As a result, both the defensive strength and restoring force of his body had taken a huge leap, which shocked everyone.
On his glittering bones, dark-purple muscles, meridians, and blood vessels were growing quickly. Very soon, as Xiang Yu had fled merely a distance of tens of miles, when the growth of his body had completed. It was taller and burlier than his original body, filled with big chunks of muscles that were glinting like they were made of strong alloys.
In the meanwhile, the Banner of Chiyou was waving and flying at an incredible speed, and it looked like in the next moment it would bring Xiang Yu into the depth of Meng Mountains. Suddenly, not far further, a pillar of dark fog towered into the sky. From it came flying out eight alligators, each having two horns growing on top of their heads, their mouth wide opened, and thrusting towards Xiang Yu.
As Xiang Yu's body had just restored, he was still very weak at the moment. When these alligators leaped and smashed onto him, he was immediately thrown tumbling to the ground. The Banner of Chiyou rolled and unleashed a blood-red beam that coiled up five alligators and brought them a few hundred feet into the sky, then threw them out forcefully. However, a few alligators managed to rip a deep wound on Xiang Yu's chest, causing sticky blood to keep spraying out from it.
"Who dared to hurt me?" Xiang Yu roared furiously.
A sudden thunderclap echoed out. A chariot pulled by four horses and escorted by a group of several hundred guards flew out from that mountain ridge.
In the chariot, a young man stood with his back straight. He was clad in a dark robe, head mounted with a dark golden crown, and had a handsome and delicate visage. An image of eight dragons slithered through a cloud was embroidered on his dark robe, while in his hand was held a spear. "Xiang Yu, you will be dead here today!" cried the young man, "Is Yan Dan here? I am Ying Ziying from Great Qin, and I am here to settle the score with Xiang Yu, as I was killed by him in the past! Yan Dan, oh Yan Dan, isn't it delightful if you can join hands with me and kill this Xiang Yu?"
Princess Zhang Le blinked, "Ying Ziying? Who is this guy? He too is cultivating the Nine Dragons Cauldron Grand Magic, and has already formed the power of eight flood dragons!"
Beside her, Wu Qi took a deep breath and said, "Ying Ziying... Most likely, he is one of the members of Ying Zheng's imperial clan?"
Ying Ziying, the last ruler of the Qin dynasty in those years, the Emperor Ziying! 
 Emperor Ziying - He was the third and last ruler of the Qin dynasty, ruled over a fragmented Qin Empire for 46 days from mid-October to early December in 207 BC. He was eventually killed along with his family by Xiang Yu. (Source: https://en.wikipedia.org/wiki/Ziying)