Most likely, Cao Yun had spent around ten days in the Blood Abyss already. Although the pain was constant, he was never able to get used to it. After all, it was always devouring his flesh as he was reforming it. Thankfully, he had fully replenished his Qi not long ago or he would have been in an even more precarious situation. Since he was now completely alone, he pondered some time on his course of actions.
By now, he was thoroughly convinced that his only chance to survive this was to absorb some of this Blood Abyss. Otherwise, he would just deplete all of his strength bit by bit until the moment he would simply either die or be unable to protect his major organs and be consumed. Thus, his survival hinged on his blood cultivation ability. As such, he rummaged through all his knowledge, making sure he had not overlooked anything.
After much consideration, he finally decided on the best way to do what he had to do. Until now, he had been able to protect a large portion of his blood thanks to the quality of the Drop of Wrath. His blood was indeed extremely heavy, but not as heavy as the blood within the Blood Abyss. As a consequence, some of his blood had indeed been absorbed into the pit as well. However, his Golden Blood was completely safe for now. In fact, the Golden Blood had replaced most of his original blood by now.
In 'Crimson Inferno Road', Cao Yun had used the 'Fate Devouring Gate' technique. As its name suggested, it consisted in absorbing the blood essence of someone else. In fact, he had used it to absorb some of Demon King Mo Wang's blood essence after their very first encounter. The best thing to absorb though wasn't blood essence but Golden Fate, a physical manifestation of one's prenatal Jing. It was even a catalyst in the formation of one's Golden Blood. Prenatal Jing was extremely difficult to increase, one could only try to improve its quality. By practicing 'Fate Devouring Gate', one's Golden Fate could indeed be improved, increasing both one's potential and lifespan. Prenatal Jing was used to produce Qi and would ultimately run out, causing old age and death.
But this technique alone wouldn't be enough. Indeed, Cao Yun had made some experiment. When he had tried to absorb some of the Blood Abyss, the opposite happened. No matter how much he tried to resist, the Blood Abyss was simply too violent to be tamed. In fact, even a late Accomplished Demon would probably have been devoured by such a capricious ocean of blood. Thankfully, Cao Yun had his Drop of Wrath that was the bane of this blood. Thanks to it, he was able to survive his little experiment.
His best chance was to use the Drop of Wrath to subdue the Blood Abyss before absorbing it. However, if he let the Drop of Wrath out of his heart, the Blood Abyss would probably try to devour his organ. He could regenerate much of his tissues, but not everything. Without a heart, without his Middle Dantian, his blood cultivation would surely be crippled and he would quickly be devoured whole with or without the Drop of Wrath. At that point, he would most likely only be able to survive within the Drop of Wrath itself. But he wasn't a Spirit Warrior and his soul couldn't survive long outside of his own Upper Dantian.
There was another way though. If he couldn't bring the Drop of Wrath to the Blood Abyss, he could bring the Blood Abyss to his Drop of Wrath. Cao Yun tried to find a better way but nothing worked. In fact, his situation was getting more and more desperate. When it was desperate enough and he had no other alternative, he steeled his resolve. Sending even a small fraction of the Blood Abyss within his heart was extremely risky. After all, if he lost control, it would attack his heart.
Until now, the Blood Abyss had been trying to get into his Middle Dantian to take the Drop of Wrath. But at the same time, it seemed to be too afraid to go all the way. In fact, even if Cao Yun tried to force it, the Blood Abyss would do everything not to go too close to his heart. Thankfully, Cao Yun had worked on both 'Storms in the Crimson Furnace' and 'Drowning One's Heart in Blood' to improve his blood cultivation. Both methods had very similar principles. In short, they consisted in sending as much blood as possible within one's heart in order to temper it. While 'Drowning One's Heart in Blood' put the emphasis on Fire Qi to fill one's Middle Dantian, 'Storms in the Crimson Furnace' was indeed only aiming at one's blood.
Because he had worked on them both for some time, Cao Yun was proficient enough to force some of the Blood Abyss in his heart. However, there was still one major problem. In order for this foreign blood to enter his heart, Cao Yun only had one access, one of his three Flood Gates, Shendao the Heart Gate. When it came to his own blood, he could simply go through his bloodstream. But it wouldn't work for the Blood Abyss as it would consume his veins and arteries before it could get near his heart. Then, he had to force it through the Flood Gate he was currently working on. Any mistake would mean being crippled or killed.
Even though Cao Yun had a good control over his acupoints, using them for Qi and for blood were two different issues. Besides, it wasn't just any blood, it was a foreign and very aggressive blood hell-bent on consuming his flesh.
With no other choice, the young man did everything he could to improve his chances. First of all, he pushed the world tree's vitality to its limit, focusing as much as he could in his Shendao without endangering his meridians, still protected by it. He even used his own Golden Blood to coat the region around Shendao. Thanks to the Rune of Fire, he controlled the Fire Qi in his blood expertly. This also added another layer of protection to his Shendao.
Finally, he decided to attempt a try. As a 5th-grade Golden Blood Child, he should practice 'Ascend the Cliff' with his Golden Blood. At the moment, he was practicing it with the corrosive blood of the Blood Abyss. Opening his Shendao of his own accord, the Blood Abyss got into it immediately. As soon as enough got inside, he tried to close up the acupoint as much as he could. A throbbing pain pierced his chest as though his heart was about to explode. A burning sensation spread from his upper back where the Shendao was, all the way to his heart. But it stopped just before his main organ.
In fact, the burning sensation was trying to get away. As much as the Blood Abyss was attracted to his Drop of Wrath, it was also too fearful to get near it. Thus, it literally tried to leave through the Shendao it had come through already. From both sides, the Blood Abyss was either trying to get in or to get out. Within, it was raging to leave his body. Without, it was attacking to get in. At the same time, the Blood Abyss kept on devouring his ever-growing flesh.
Once more, Cao Yun circulated his mind cultivation to resist the pain and keep his focus. He had to funnel the Blood Abyss already trapped in him through his heart. However, it wasn't cooperative at all. Pushing his mind cultivation, Cao Yun also tried to remember the calligraphy that was probably the Weaver of Souls'. At that moment, he felt that the Blood Abyss in his chest was a bit calmer, as if the Weaver of Souls' influence was soothing it. Without any hesitation, Cao Yun used this moment of relative calm to send as much of the intent of the Drop of Wrath in it. With one move, he tried to force all the captive Blood Abyss into his heart. Contrary to his expectations, it really did work.
Now that the Blood Abyss was in his heart, he had to count on the Drop of Wrath. Thankfully, he wasn't disappointed at all. His Drop of Wrath devoured it all in an instant. The Blood Abyss didn't even have time to cause any problem within his heart. Against such a powerful blood, it had no chance at all. After all, it had belonged to an Immortal Demon at the very least, and probably much stronger in reality. There was even a chance that Axiu Qian had gone all the way to the ninth realm of blood cultivation, and had become a Calamity. But Cao Yun couldn't be sure. After all, even Cleansed Asura had not reached an equivalent level.
Thanks to this Blood Abyss being absorbed, Cao Yun recovered some of his strength. At the same time, he felt his mind cultivation improve a tiny bit. It wasn't much, but he did feel as though his mind was refreshed and the Turbid Demons had become weaker. Most likely, they had stayed as strong as before, but his own mind had become stronger. It wasn't much, but with his great sensibility, he could still feel it clearly. There was no doubt possible. The Blood Abyss truly contained some of the blood from the Weaver of Souls and he had written 'Sealing the Seven Demons in the Nine Peaks'.
Taking some time, Cao Yun made sure that his Shendao was safe. For several days, he kept on doing the same thing. It was enough to keep him alive, but he had to do much more than that. First of all, he had to gain enough strength to swim back up within this extremely heavy and dangerous blood. But he also needed to garner enough strength to escape from the Monastery of Bliss and Repose. High Mother Qin Xue was probably even more dangerous than this blood pit. On the other hand, he had no idea what was happening outside. Maybe Xixue was in danger, or even dead already.
Since all that was outside of his control, Cao Yun used his mind cultivation to chase all his thoughts. For too long, he had been full of doubts about many things. As much as he wanted to change, he knew that this was a part of himself. When he was younger, he had a hard time making proactive decision, but even now he still was unsure of the right thing to do. The only thing in which he was certain was his martial arts and his cultivation. Thus, he decided to solely focus on his training. And he did.
The process of pulling in some of the Blood Abyss within his Shendao was excruciating. Even after doing it several times, it wasn't any easier. In fact, he was only able to absorb enough blood so he wouldn't deplete his own blood and Qi. However, he still wasn't able to stave off the Blood Abyss that was consuming his flesh over and over again. In fact, Cao Yun was forced to rest for days between each time he absorbed some Blood Abyss.
In the meantime, he worked on his cultivation. His only way to forget the pain was to focus on something else, to put his mind to work. And this work was obviously his cultivation. First of all, he always made sure that the two Turbid Demons were kept under tight lock. Each time he absorbed some of the Blood Abyss, he realized that they became easier to control. Before long, they would be fully subdued. At that time, he could try to chain them down to his Nine Soul Peaks so they would join his Flying Poison. In fact, both the Unclean Evil and the Stinking Lungs were starting to materialize themselves within the Drop of Wrath. They were getting very close to being fully fleshed out. That meant that the Drop of Wrath would really become stronger.
On the matter of his blood cultivation, his Shendao was obviously getting tempered. Because of the nature of the Blood Abyss, he simply couldn't take more of it each time as it would endanger his life even if his Shendao could take it. After only three weeks, Cao Yun had officially crossed the threshold of the 6th-grade Golden Blood Child. This cultivation level was called 'Gold Heats Up Heart's Passions'. It simply consisted in tempering one's heart, and the entire chest cavity as a matter of fact. Since Cao Yun had already worked on his Middle Dantian, it wouldn't take long for him to break through. Besides, the Drop of Wrath was also strengthening his heart. But now, he could make his Golden Blood travel through his entire spine, all the way to his head. That would be the final Flood Gate, Fengfu the Palace Gate.
What progressed the fastest though wasn't either his mind cultivation nor his blood cultivation. During all this time, Cao Yun had focused on protecting his meridians and Dantian rather than his flesh. Thanks to the incredible bloodline granted to him by the Drop of Wrath, he could even regenerate his limbs and some organs. Most demons couldn't do such a thing, at least not to such an extent. Maybe a powerful Golden Blood Child could grow back a finger or some small part of a minor organ. But only a much more powerful demon could regenerate their own flesh. In fact, some demon, like Axiu Qian, could regrow their entire body from a single drop of blood as long as their soul endured. Cao Yun's resilience wasn't to this level but it was still prodigious. However, it applied to flesh, not to his meridians and Dantian that were unique to humans.
For several weeks, his meridians were imbued with the full vitality of the world tree while being assaulted by the Blood Abyss. After taking car of his other cultivation systems, Cao Yun always made sure to circulate his Water Qi within his meridians. Like that, he could temper them through the use of Wood, Fire and Water. As an alchemist, it was relatively easy for him to handle all of that despite the debilitating pain.
For several days that turned to weeks, that then turned to months, Cao Yun cultivated in the deepest parts of the Blood Abyss. Clearly, this had been the very worst experience of his entire life. There was not a single instant in which he was not in pain. Not only was this a physical pain, but this was also a mental pain. However, he also felt perfectly at ease there. He had no decision to make, he simply had to stay alive and work on his cultivation. Even if he screwed up, he would be the only victim. Holding the fates of others wasn't something he really liked after all.