Cao Yun and Feng Yingyue had almost reached the very last stage of their dual cultivation. Before that, they still had to go through 'Furnaces and Cauldrons Union'. Honestly, they were almost already there. This stage consisted in a complete union of the two partners, both physically and spiritually. As Feng Yingyue's Yellow Court exploded, a vast energy radiated throughout the two cultivators.
Suddenly, no limits existed anymore. They were just one. In fact, they couldn't feel the boundaries of their flesh or even their minds or souls. Just like in their merged sea of consciousness, they felt as though they were spread infinitely and eternally. Time and space lost their meaning. The sensation itself was pure bliss. Most of the energy unleashed by Feng Yingyue's explosion was absorbed by Cao Yun's body. In particular, his Solar-Orchid Flame devoured an incredibly large amount of Fire Qi and even Essence Fire.
An instant could last forever and an eternity could be eclipsed in the blink of an eye. Both partners were completely lost in one another. Strangely enough, by losing themselves, they also found themselves. By dissolving the sense of boundaries, Cao Yun and Feng Yingyue's souls found something new. Both of their perspectives began to change, even regarding the matter of the self. It was very subtle, so it might take them centuries to fully understand this sensation. Their two minds and all of their souls were forming only one entity at the moment and they had lost the sensation of being individuals. It was very difficult to fully grasp it. Indeed, if they tried to focus on it, the sensation disappeared. Besides, they didn't want to focus on it or even explain it, they simply wanted to bask in this great sensation.
At last, they could enter the very last stage of 'Twin Flesh Furnaces, Soul Cauldron'. Only if all other layers of the method had been successful could one even attempt this last step. It was 'Sublimation of Twin Fires'. During the conception of a child, the man would give his Yin Jing and the woman her Yang Jing. By using the principles of conception, 'Twin Flesh Furnaces, Soul Cauldron' could serve to improve both of their cultivations by strengthening their Soul Embryos. After all, Soul Embryos were similar to children being conceived by the clash of Fire Qi and Water Qi.
During this last stage, it was also possible to improve one's pre-natal Jing. Such a feat was incredible, even for alchemists. But this couldn't easily be achieved. Besides, it wouldn't work indefinitely. Whether Cao Yun and Feng Yingyue succeeded in this session or not, they would barely gain any benefit from another session before a very long time, apart from pleasure, of course. Dual cultivation was extremely intense and using it too often wasn't a good idea. Indeed, both Cao Yun and Feng Yingyue had pushed their bodies and their souls to their limits. Moreover, it was extremely difficult to stay this intense in every session. Dual cultivation wasn't like meditating at all.
Within Feng Yingyue's Yellow Court, her Soul Embryo was being formed by the Fire Qi and Water Qi coiling around each other. But then, she felt a powerful Water energy coming from Cao Yun's body. It was his Yin Jing. In return, her own body produced an intense Yang Jing full of Fire element. Somehow, Feng Yingyue's body could naturally produce large amounts of Fire element, not only in her Qi but also in every aspect of her being. In other cultivators, this would have suggested a deep imbalance of Fire, but Feng Yingyue had no symptoms of such a thing. As an alchemist, she would have sensed it.
Under the influence of Cao Yun's Solar-Orchid Flame, Feng Yingyue's Fire got more and more vibrant. It was as if the seed and Feng Yingyue's Fire had similar origins. The mere presence of the seed was enough to resonate with Feng Yingyue's nature.
Anyway, both of these Jing also penetrated Feng Yingyue's Yellow Court. Her Fire Yang Jing was coming from her heart, fueled by Cao Yun's heart which was pressing against her chest. His Water Yin Jing was coming from his loins, sent by Cao Yun's Golden Fate in his Lower Dantian. As such, those two energies were just like her Lower Dantian's Water Qi and her Middle Dantian's Fire Qi. As a result, they were both nourishing her forming Soul Embryo. If they had wanted to, they could have conceived a child at this moment, but it wasn't their intent.
Very soon, Feng Yingyue finally developed her Soul Embryo. It pulsated with vibrant silver energies that spread throughout her body and then even went into Cao Yun's flesh. Not only did those waves of spiritual energies activate Feng Yingyue's soul, but they also interacted with Cao Yun's Soul Embryo. Their two glistening bodies were floating, but not only under Cao Yun's spiritual senses. Now, Feng Yingyue's spiritual senses were part of it too. In fact, both of their spiritual senses intertwined.
Although Feng Yingyue's Lower Dantian and Middle Dantian had been depleted by her breakthrough, they began to fill up immediately. The Yang Jing and Yin Jing were already nourishing her Soul Embryo. Since she had become a 1st-grade Spirit Warrior, her cultivation had been progressing faster and faster. Indeed, the 1st-grade Spirit Warrior stage was known as Nourish the Embryo. Its main point was to fill up the depleted Dantian in order to feed the newly formed Soul Embryo. Right now, it was already happening. In fact, it was more than likely that Feng Yingyue would jump all the way to 2nd-grade Spirit Warrior.
From there, it would be harder to make any progress as it was about slowly awakening the Soul Embryo. Trying to force the Soul Embryo awake with dual cultivation would probably be a bad idea. Listening to the Soul Embryo and taking the time to know it and its reactions better was also part of the process. Besides, it was essential for the following stages. However, she could easily break through to the 2nd-grade Spirit Warrior stage without any problem for her future cultivation.
On the other hand, Cao Yun was also breaking through. As he felt Feng Yingyue's body shake and quiver in his embrace, he also felt her warmth as her body was producing incredible amounts of Fire element. Even her newly formed spiritual senses were full of Fire element. And they were pressing on his Soul Embryo. With his Solar-Orchid Flame and his Rune of Fire, this amount of Fire element wasn't dangerous for Cao Yun. In fact, the Solar-Orchid Flame was absorbing most of it since they appeared to have the same origin.
Wave after wave, Feng Yingyue's explosions kept radiating Essence Fire. Now that her Soul Embryo was also pulsating, those waves were affecting Cao Yun's Soul Embryo. Moreover, all the new sensations Cao Yun had just experienced were being channeled by his soul directly into his Soul Embryo. Very slowly, his Soul Embryo had been altered. Without Cao Yun even noticing it, his Soul Embryo was now a perfect copy of himself. It had all of Cao Yun's features. In the center of his sea of consciousness, there was a small Cao Yun made entirely of silver. As if waking from a very long dream, his Soul Embryo opened its eyes. Behind his eyelids, there were two golden-reddish beads.
Suddenly, a powerful radiance drowned the entire universe. Even Feng Yingyue's sea of consciousness was bathed in it. Cao Yun had officially stepped into the 6th-grade Spirit Warrior stage. However, it didn't just stop there. Dian Mo, who wasn't observing Cao Yun and Feng Yingyue's dual cultivation, was also shaken by what was going on. This intense radiance affected him too. The Palace of Supreme Wisdom's spirit felt stronger than ever. Even now, he had still not fully recovered from everything he had been through, almost but not completely. That being said, this radiance not only restored him, but it even pushed him higher. It wasn't much unfortunately. Still, it was extraordinary. Most likely, it had worked because Cao Yun felt close to Dian Mo so the energy unleashed by his Soul Embryo was compatible with Dian Mo, as it was compatible with Feng Yingyue.
Thanks to Cao Yun's mind and soul cultivation, it didn't end here at all. Parts of his soul were already being pulled into his Soul Embryo. But then, he also felt a force pushing his soul inward. This force came from Feng Yingyue's explosions. Her own Soul Embryo was sending wave after wave that was crashing on Cao Yun's soul, pushing it in with increasing force. At the same time, his Soul Embryo was pulling his soul in through those intense red beads that were his eyes.
One of the main obstacles during the 6th-grade Spirit Warrior stage was a sensation of total annihilation. Indeed, the point of this stage was to send one's soul directly into the Soul Embryo. But this caused many existential crises to cultivators. For most cultivators, it created the sensation of falling into pure oblivion and complete obliteration. It was the feeling of falling into the void. Of course, intellectually, they knew it wasn't the case, but it wouldn't change anything about the sensation itself. Once the soul was within the Soul Embryo, the sensation would completely cease to be. But the point was quite literally to put one's soul into something that was living within their own soul already. Such a strange thing wouldn't happen easily.
Moreover, the Soul Embryo could always reject the soul at any given moment. Then it would create even more anxiety because the cultivator would fear damaging the Soul Embryo as well. In fact, most of this stage was psychological. But once the soul was within the Soul Embryo, it became much stronger and much more resilient. Indeed, after that, since the Soul Embryo could survive outside of the body after death, it was possible for the entire soul to survive, not just bits and pieces. This was a true qualitative change. 6th-grade Spirit Warriors could live for around a millennium and a half but 7th-grade Spirit Warriors could endure for two millennia.
Cao Yun's Soul Embryo was made entirely of silver. As such, it was reflecting all of Cao Yun's sea of consciousness. Bit by bit, everything in his sea of consciousness appeared clearer and more vivid. It was as if a fog was being slowly lifted. At first, only the infinite sky and eternal ocean were visible. Then, the seven Piercing Stars became perfectly visible as they were very bright. One by one, Cao Yun's Five Aspects appeared as well, like so many new stars. With its deep red, the Drop of Wrath was clearly visible as well.
It took some time but all the golden writings and runes all around appeared as well. Soon, they were perfectly readable. Even his Nine Soul Peaks appeared despite not producing any light themselves. In fact, it literally became impossible to tell the difference between his sea of consciousness and the Soul Embryo. One could look at the Soul Embryo for eons without realizing that it was a Soul Embryo. Unless it moved, it was impossible to tell the difference.
Cao Yun himself could not tell the difference at all. Besides, he was already lost within Feng Yingyue's complete embrace. At the same time, it was also what was speeding up the process. Indeed, even with all the relaxation possible, every cultivator would instinctively fight the force pulling their own souls within. After all, it could be terrifying. But Cao Yun escaped from this fear as he had already lost himself. Since his being had melted into Feng Yingyue's, he couldn't oppose any resistance to this phenomenon. In fact, it was as if he was a mere spectator.
He was looking at his own sea of consciousness. Even his intent was being pulled in. Suddenly, he realized that he wasn't looking at his sea of consciousness, he was looking at his own Soul Embryo. But when he turned his intent to look at the sea itself, it was gone. Once again, he was faced with the Soul Embryo's silver surface reflecting the sea of consciousness. At that moment, Cao Yun realized that his intent was already within the Soul Embryo. In fact, his Soul Embryo and his sea of consciousness were now one and the same. Or to be more accurate, his sea of consciousness and his very soul were encased within his Soul Embryo. It was yet unclear whether the boundaries of his Soul Embryo were also the boundaries of his sea of consciousness.
In Cao Yun's Upper Dantian, a vibrant light exploded outward. He felt all of his nine chambers vibrate. This light spread and also affected Feng Yingyue who was practicing the same mind and soul cultivation method. As such, she felt her 'Sealing the Seven Demons in the Nine Peaks' method circulate with more and more strength. All of that was strengthening her Upper Dantian. Thus, it would make her 3rd-grade Spirit Warrior stage that much easier when she finally got there after awakening her Soul Embryo. Unfortunately, it couldn't awaken her Soul Embryo for her.
Anyway, Cao Yun and Feng Yingyue had reaped a lot of benefits. She was now a 2nd-grade Spirit Warrior and he was a full-fledged 7th-grade Spirit Warrior. Now, he had to practice Spiritual Harmony. In other words, he had to fully merge and fuse his soul and his Soul Embryo. For the moment, his Soul Embryo was a vessel containing his soul. But it had to become his soul itself. For great cultivators, it would take somewhere between ten to fifteen years. To be fair, Cao Yun had already exceeded everything that was thought possible in terms of speed of cultivation.
On one hand, he was very excited by that idea. On the other hand, he was worried that he would limit his own growth. If only he didn't have the fear of Emperor Weide killing his sister, he would have slowed down, but he couldn't. He had to grow as strong as he could. Still, he wasn't willing to sacrifice his future. So he wouldn't overdo things.