After absorbing this fourth wave of bright light, Cao Yun realized that it was getting less effective on tempering his Upper Dantian. But this wasn't a bad thing. In fact, it proved that his Upper Dantian had reached the limit or was very close to it. To improve it even a tiny bit was as difficult as moving Heaven and Earth. Thus, Cao Yun stopped working on it. Maybe some pills would help it to push it a bit further, but this was not the time to do so. Indeed, Cao Yun simply couldn't control his body at all, everything that he was was within his sea of consciousness and his entire intent was directed inward. If someone were to attack him at that moment, Cao Yun wouldn't be able to do a thing about it.
Cao Yun's only defenses were his array formations and Hongyu who had stayed outside. Cao Yun had not even had any time to warn her but she was smart enough to figure out what was going on. And he knew it. Indeed, Hongyu had felt Cao Yun's array formations. Immediately she understood that he was breaking through and setting up defenses. Thus, she stayed around the Temple of the Lesser Blood King and even summoned some of her strongest demonic beasts to guard it.
While time had basically become meaningless to Cao Yun, Hongyu had kept guard on the temple for two weeks already.
The young man used the last bits of the fourth wave in order to try and help Dian Mo. The remainder of the fourth wave penetrated the Palace of Supreme Wisdom. Now that Dian Mo had finally awaken, he was able to use this energy in order to recover some of his strength. Even though he wanted to help Dian Mo, Cao Yun wasn't sacrificing his own cultivation. He had sent this wave of energy into the Palace of Supreme Wisdom because it had almost no effect on him anymore. For the next wave though, he had a better idea. This was something he had read in 'Sixty-Two Transformations of Soul and Mind', another document owned by Cleansed Asura.
In fact, 'Sixty-Two Transformations of Soul and Mind' was an anthology of various authors reflecting upon the soul and mind of humans. There wasn't anything too concrete and was much more a compilation of philosophical texts more than anything else. However, some author had pointed out a few ideas about cultivating one's Soul Embryo. Now that Cao Yun was breaking through, he wondered whether he should try to apply it. And after feeling those four waves, his resolution was firm. Since his Upper Dantian had reached the pinnacle for now, he would try and achieve a large success in the 4th-grade Spirit Warrior stage.
This fourth stage consisted in having his Soul Embryo ascend directly into his Upper Dantian. There were two main difficulties in this endeavor, usually. First of all, the Upper Dantian had to be tough enough to resist the presence of the Soul Embryo and the increased pressure. Most cultivators tried to keep their Soul Embryo up there for increasingly longer periods of time. Indeed, even after strengthening their Upper Dantian, it was still hard to bear the increased pressure. In fact, it was even possible to injure or kill oneself if the cultivator wasn't careful.
The other problem was about moving the Soul Embryo in itself. Indeed, it had to go through the Du Mai, the Governing Vessel, the large meridian in someone's back. But to Cao Yun, this wasn't much of an issue. Indeed, when he was only a Golden Blood Child, he had learned to open and control his Three Flood Gates, Mingmen the Life Gate, Shendao the Heart Gate and Fengfu the Palace Gate. As a matter of fact, those Flood Gates were exactly the points that were also dangerous for humans. Although demons had no meridian, those gates were also delicate locations. For example, Mingmen the Life Gate was directly connected to the kidneys where one's Prenatal Jing was so if unchecked energy were to spill out of this gate, the result could be catastrophic or lethal. In the same way, Shendao the Heart Gate was obviously connected to the heart while Fengfu the Palace Gate was linked to one's head and brain.
When he had cultivated his Golden Blood Child realm, Cao Yun had learned how to manage those Three Flood Gates in order to send his blood and marrow into his spine and toward his Upper Dantian. Now, he could use them in order to send his very Soul Embryo. As such, he was already closer to his goal than any other human who had just broken through to the 4th-grade Spirit Warrior stage. In fact, Cao Yun was a bit exhilarated and euphoric. He might be able to advance his Qi cultivation by leaps and bounds. It might be possible for him to catch up with his blood cultivation. If he could, he would obviously be much stronger than any other cultivator of the same level.
Finally the fifth wave of light appeared. Thankfully, it still wasn't the final one. Although he had never felt it, Cao Yun was certain that he would recognize the sensation of the final wave. If everything went well, he could still use five more waves of light. How far could he go by harnessing all this energy?
In 'Sixty-Two Transformations of Soul and Mind', a philosopher had talked about using the very waves created by one's Soul Embryo to move the Soul Embryo itself while it was still in the process of waking up. That woman had thought that sending a still dormant Soul Embryo in one's Upper Dantian would help make one's Upper Dantian more familiar with it. But in the end, one would be forced to send it back once it was fully awakened as the Upper Dantian could not bear the pressure of the spiritual energies unleashed by a fully awake Soul Embryo. However, it didn't apply to Cao Yun as he had already tempered his Upper Dantian to the limit. If his Upper Dantian could resist the full force of an entire wave of energy from the Soul Embryo's awakening, it could harbor the Soul Embryo itself.
What was really dangerous of course was to move around a dormant Soul Embryo. And moving a Soul Embryo while it was waking up was even more dangerous. That was why this philosopher had imagined using the wave as a form of shield around the Soul Embryo, it would simply drift along the flow of this wave of energy. That meant that Cao Yun had to channel of this fifth wave directly into his spine and his Du Mai. If he had not tempered his Extraordinary Vessels, meridians, bones and flesh, Cao Yun would have never attempted that. In 'Sixty-Two Transformations of Soul and Mind', this was just a thought experiment but no one had been crazy enough to try it out. Cao Yun had the sturdy body of an asura and the powerful meridians of a human so he dared, but even then, it was risky.
The fifth wave of light had been completely suppressed and condensed into Cao Yun's Huang Ting. As such, his Soul Embryo was bathing in it. Suddenly, Cao Yun channeled all of it directly into his Mingmen and his Soul Embryo followed. Besides the wave of silver light, Cao Yun was keeping his Soul Embryo surrounded by his Turbid Demons to check on it and to protect it. Then, he released the control he had on the wave of energy. It pulsed through his spine. As a powerful geyzer, it erupted into Cao Yun's Du Mai. His Soul Embryo, protected by the seven Turbid Demons, shot through his spine and went through his Fengfu the Palace Gate.
Even with Cao Yun's tempering of his Three Flood Gates, he felt intense pain through all of them. In fact, his bones and the flesh around it was slightly damaged but none of his organs were affected thankfully. If he had been a bit weaker, the damage would have been way worse. He would have still been successful but his body would have suffered the consequences of his recklessness.
In fact, Cao Yun realized that he had been too reckless. He had already realized that he should cultivate in a more restrained way. But the exhilaration of his current breakthrough as well as the necessity to improve his cultivation had gotten the best of him. Thankfully though, he had succeeded. Indeed, his Soul Embryo was now residing directly into his Upper Dantian and it literally appeared within his sea of consciousness.
In the midst of his Nine Soul Peaks, Cao Yun could see the image of his silver embryo. It looked like a small infant with no particular features. In fact, it didn't even have a face yet. For the moment, it was still in a fetal position but there was no doubt that it was slowly waking up from its slumber. Technically, Cao Yun was a 5th-grade Spirit Warrior now. As soon as his Soul Embryo would fully wake up, Cao Yun would be a middle Spirit Warrior.
Obviously, temptation was high for Cao Yun to try and go further and further. Besides, now that his Soul Embryo was literally in his sea of consciousness, harnessing the power of the spiritual waves would be even easier.
In the fifth stage of the Spirit Warrior Realm, also known as the Embryo Realm, one had to nourish their Soul Embryo with their soul. The point was to send their emotions and personality into the Soul Embryo so it would take on the shape on its progenitor. In a sense, it was like bringing up a child. But it was fundamentally different in the sense that the goal was for the child to become perfectly identical to the parent and that the child had absolutely no awareness and no self at all. It was just clay for the cultivator to mold.
Cao Yun's silver Soul Embryo was in the middle of his Nine Soul Peaks, where his Five Aspects were. In other words, it was right in the center of Cao Yun's mind and soul. His seven Po and three Hun were surrounding it while the characters related to them were floating above it. At the same time, all the mental representations of his mind were hovering above it as well. Without any hesitation, Cao Yun circulated his mind cultivation. High in the skies, his Shen the Fire Spirit was burning with bright red flames. With his Rune of Fire, Cao Yun controlled them with extreme finesse.
Those flames completely encased Cao Yun's Nine Soul Peaks into a dome of fire. When the sixth wave hit, it was captured by this dome. As it happened, the dome almost ruptured but thanks to his Rune of Fire, Cao Yun was able to control it enough so it would endure. Thus, the entire wave of silver light was focused on Cao Yun's Soul Embryo and Turbid Demons, even on his Five Aspects and the Drop of Wrath.
One of Cao Yun's hopes was to harmonize not only his soul and his Soul Embryo but also his Demon Soul that was the Drop of Wrath. As of now, it was almost complete as only the Devouring Robber was fully formed and tamed. After that, Cao Yun would need to still merge all of his Turbid Demons into a singular Demon Soul. But his Drop of Wrath was already achieving this goal, more or less. Still, he would need to go through the process nonetheless, but it would be faster. If Cao Yun could merge his soul, his Soul Embryo and his Demon Soul, he hoped he could achieve something similar to the devas. Unfortunately, he had no real point of reference. Indeed, Cleansed Asura had been a human and Axiu Qian had been an asura. Thus, Cao Yun barely knew anything about the cultivation of the devas except for intellectual things. He had no memory of firsthand experience.
The seventh wave came. Once again, it was completely contained within the dome of fire, tempering and strengthening Cao Yun's mind and soul. In the dome of fire of Cao Yun's Shen, the Palace of Supreme Wisdom was also there and benefited from the experience. But it didn't try to take in more energy than necessary. To be fair, it simply couldn't. First of all, Cao Yun was in control. But even without Cao Yun's restraint on the energy, Dian Mo couldn't have absorbed all of it. If he had tried, he would have died for sure this time. That being said, this energy was extremely beneficial to Dian Mo who was a pure spirit without any body. In a sense, he was very similar to a Soul Embryo.
Then came the eighth wave. This one didn't contain more energy but it was much more violent. It almost tore through the dome of fire. Cao Yun himself had a hard time controlling it. This time, he was even forced to let go of some of it so it wouldn't damage his Soul Embryo or his Turbid Demons. As his breakthrough was reaching the end, it was indeed becoming much more primal and violent.
In the physical world, powerful waves of spiritual energies were being released by Cao Yun's body. He was now levitating above the floor and the Temple of the Lesser Blood King was full of cracks. Even the array formations he had set up were on the brink of collapse. The raw energy released by his body was simply too much for his surroundings. If he had used real array formations and not just plates, they would have resisted. But those array formation plates were less resistant. Besides, they were less attuned to the environment around them.
Now Cao Yun was waiting for the final wave. In total there could only be nine waves and then a final one as the Soul Embryo would wake up for good. So Cao Yun was certain that the final wave would soon erupt, either it would be the next one or the one after that. But he could barely stand the eighth wave so he really wondering whether he should still try to harness the energy of the final one. Yes he could improve his cultivation but he had already risked a lot to achieve a great success.
As soon as he would open his eyes, Cao Yun would be a 5th-grade Spirit Warrior and even closer to becoming a full-fledged 8th-grade Accomplished Demon. What some achieved in decades if not centuries, Cao Yun had achieved in a matter of months if not weeks. Of course, he had been able to go from 2nd-grade Spirit Warrior to 5th-grade Spirit Warrior thanks to his mind cultivation and blood cultivation. But this was still a very impressive feat.