First, Cao Yun began to work in his sea of consciousness, imagining several different ways to refine this pill. With his Chamber of Heavenly Court, he was able to accelerate his thoughts and could thus spend several days worth of work in his mind in a single double hour. On the side, Dian Mo was observing him and was quite impressed by Cao Yun's obstinacy. No matter how many times it failed, Cao Yun would try something new. Of course, he was just imagining the process so he could be wrong, but it seemed right to Dian Mo.
Cao Yun was working with more than eighty cauldrons at the same time while imagining all kinds of possible ingredients and methods. Even for him, this was terribly exhausting. Just to support this effort, he had set an array formation and was using high spirit stones. This was saturating his surroundings with raw Qi. As such, his vitality had improved. But the strain on his mind was hard to handle nonetheless. However, this was also a way to temper his mind. Soon he knew that he would face a terrible trial as he would face a 4th-grade Spirit Warrior's Soul Embryo.
Even with his Drop of Wrath and a bit of Dian Mo's help, this was going to be difficult. Besides, he might even be forced to fight something else that was lurking in the back of his mind. So he could use this opportunity to also improve his mind. In particular, he was working on his will. Zhi the Water Will was looking like a liquid metal under the effects of Shen the Fire Spirit.
After more than a thousand failures, Dian Mo began to give some pointers to Cao Yun. Although he wasn't an alchemist at all, Dian Mo knew more than just a bit about the five elements as well as Yin and Yang. After all, he had resided within a complex array formation for most of his life. Of course, he had a lot of expertise when it came to those subjects. Then, both of them spent a lot of time discussing and brainstorming about the creation of a new recipe for this pill. Before long, they almost forgot everything else. Dian Mo was probably one of the few who could follow Cao Yun's speed of thought since he was a bodiless spirit himself.
In the end, they spent at least eight days working on this. In Cao Yun's mind, this had been almost two months of reflection. Obviously, even with his mind cultivation, Cao Yun had been forced to rest from time to time. He couldn't keep his Chamber of Heavenly Court fully activated all the time. Furthermore, taking a break was also good for his creativity. The Chamber of Splendor was very effective in that regard too and so was his Chamber of Government to stay focused despite the fatigue.
From time to time, Cao Yun tried to refine a pill with what he had come up with at the moment. It never was perfectly what he had imagined, but it was uncannily close. However, these real attempts were essential for his mind not to stray too far away from reality. Sometimes he even only needed to make sure that some ingredients interacted the way he thought they would. Thankfully, Cao Yun was right beneath the Myriad Cherry Blossom Hall and had a lot of money. That way, he could easily get access to all the ingredients he needed to test out his theories.
By doing this work, Cao Yun's understanding of alchemy had improved even more. His 'Spiritual Sea Refinement' was now more accurate than before thanks to all the tests he had performed. If he tried to refine a Heaven pill, it would be easier for him. Of course, he still wasn't sure he could actually reach the requirement to be called a Heaven alchemist, but he was getting closer and closer. Most likely, he would become one before becoming a Spirit Warrior. That was unheard of in the history of the Hongchen Kingdom. But to be fair, his mind cultivation was also unheard of. Once again, he realized how dangerous it was.
After the end of the first week, Cao Yun was ready to test out a pill recipe for the Merging Minerals and Seas pill that only cost ten taels of gold. That was five time less than the original cost of the pill. But then, he had to make sure that the refinement process was a success as well, that the pill had the same effects and that the quality was good.
Instead of using seven ingredients, Cao Yun would be using twenty-one ingredients. Each one was way cheaper than any of the original ones. In fact none of the original ones remained. But the refinement process would be almost four times longer and it was impossible to tell how complicated and difficult it would be. But in Cao Yun's mind, it was possible to achieve the results he wanted. So he got to work and refined many batches of this revised Merging Minerals and Seas pill. At first, he barely made it, with a very pitiful quality as a result. But with time, he got better and better.
Each refinement brought him some insights he then used in his mind to improve the recipe. Just knowing the right ingredients wasn't enough, he also had to find the best way to use them so that the refinement in itself wasn't too hard. Right now, the pill had to be as difficult to refine as a 3-star Heaven pill. Gaining money but requiring a Heaven alchemist instead of a Human alchemist wasn't much improvement. Thankfully, it didn't take too long to Cao Yun to figure out a better approach. In fact, he even used a strange technique he had read about once.
Among all the books he had read, Cao Yun had accumulated a lot of knowledge. However, he had not been able to digest everything yet. First of all, the sheer amount of information contained within the libraries of the Wubei Sect was insane. Even with his mind cultivation, he simply couldn't be aware of everything at once. For now, he had just remembered every single word. Every time he could, he was trying to piece things together. Knowledge was not just about understanding and remembering, it was also about making connections between things and applying them in real life. Without experience, knowledge was not that useful. It would be like a man who had learned every martial move but was unable to perform them well even though he knew the correct form. And even if could perform them well, he still had to use them at the right moment during a fight.
The technique he thought about came from an obscure manual called 'Dragon Devours Dirt'. With this technique, an alchemist had to finalize the refinement process through the use of the naked flames. Of course, this was a risky process, but it just required a bit of training to perform it well. Depending on the control over the flame, it could boost the quality of a pill by a substantial margin. The principle was quite simple, by burning the pill just after opening the lid of the cauldron at the end of the refinement process, the heat could bond medicinal essence in the air with the pill. But at the same time, it could also burn the pill. That being said, it wasn't necessarily a bad thing as it could potentially burn some of the toxins with it.
With Cao Yun's control over his flame, this was very easy for him. And it wouldn't be that much more difficult for a Human alchemist. But this added a variable as now Cao Yun had to rethink the process to also control the concentration and the nature of the medicinal essences in the cauldron by the end of the process. Since the lid had to be opened several times, some of the medicinal essences would escape. So Cao Yun had to create the right mix in his cauldron.
In the end, Cao Yun reached a good balance. His Merging Minerals and Seas pill was complete. Although the pill itself cost less than ten taels of gold, it took Cao Yun more than twenty Yuanbao to get to this point. It was almost the price of one of his cheapest True Essence pills...
Finally, he decided to refine a final batch in order to get the best Merging Minerals and Seas pill he could. The flames below his cauldron were dancing with several colors, heating up different portion of the cauldron. Some of the tongues of fire even formed loops in the air. This was a true show of art. The ingredients were flying in the air before falling into the cauldron at very specific moments. Even the trajectory of the ingredients was calculated with extreme minutia. At some point, the cauldron began to shake violently. For several minutes that turned to almost an entire hour, it seemed as though the cauldron was about to explode. However, Cao Yun was aware of what was going on. He injected his Qi within the cauldron in order to improve the quality of the refinement.
In the end, the cauldron did not explode. Instead, it slowly calmed down as the flames were dying out as well. By now the refinement process should have been over, but Cao Yun could tell that the pills weren't done. However, he had created a highly pressurized environment in the cauldron. It was full of medicinal essence as well as toxins. He took a deep breath and began the last step. The moment he opened the cauldron, a thick aroma escaped from it as several pills were floating in the air.
From the dying flames, two tongues of fire erupted toward the pills. Without the protection of a cauldron, burning a pill was usually a terrible idea. It needed to be heated up in the right environment, not burned to a crisp. Only a handful of alchemists could bake a pill without a cauldron. And they were all doing so by using their very Qi as a replacement for the cauldron. But at this moment, Cao Yun used naked fire to provide the finishing touch to that pill. 'Dragon Devours Dirt' was not strictly speaking meant as a refining technique, but as a last help to improve a pill.
When the fire touched the pill, it lasted just an instant. The flame was intense but short-lived. The goal was to condense as much medicinal essence in the air as possible in the pill before letting it cool. Some of the medicinal essence that was still lingering in the air got suddenly fused to the pill. On the surface of the pill, there were tiny burns here and there, but they were full of medicinal essence.
In the end, the best pill had reached the Pure grade. Technically, Cao Yun was thus a 5-star Human alchemist. It had retained more than 96% of the medicinal essence. Cao Yun's mastery of the fire was absolutely on point. But he was now certain that any Human alchemist could do this refinement. Of course, their result wouldn't necessarily be as good, but the techniques used were all accessible.
Once the refinement was over, Cao Yun was more than satisfied but he had a strange idea as well.
In terms of blood cultivation, Cao Yun was a 6th-grade Blood Child. As such, he was sending his blood within his bones in order to nourish them. For him that wasn't difficult at all. After all, even before starting the 'Crimson Inferno Road', Cao Yun had made his body as transparent to blood as it was to Qi. Right now, he was just consolidating his cultivation to go higher later on. However, he had not forgotten about 'Storms in the Crimson Furnace', the manual he had obtained from Matriarch Huang. For now, he was still stuck at 'Stoking the Human Flames' since he couldn't use Fire Qi within his own heart. But he had a few good ideas that could even help him during the next grade of the Mortal Warrior realm.
One of those ideas seemed a bit reckless but after succeeding in using 'Dragon Devours Dirt', Cao Yun decided to test it out. And he might even use it to help out Hongyu. He only kept his 'Aureate Grove Blaze' and restarted the fire without any cauldron.
Within his sea of consciousness, Dian Mo himself was intrigued. Everything this boy did was always intriguing. To be fair, he had been stuck in the Demon Palace for millenniums, he would have been amused by pretty much anything. But this boy always had imaginative ideas. Even his plans in Qingyun City were original in Dian Mo's eyes, albeit reckless. But this time was a bit different because Dian Mo knew a lot about blood cultivation, yet he had never imagined to do what Cao Yun was doing.
From his own bloodstream, Cao Yun took out a condensed drop of blood. Using 'Reducing the Five Sheng', Cao Yun had only condensed a hundredth of his overall blood within this drop. Despite the Fire Qi in his blood, this was nowhere near what was necessary for 'Stoking the Human Flames'. And since Cao Yun didn't want to risk absorbing too much Fire Qi, he had to resort to another means. Instead of using Fire Qi, Cao Yun would use literal fire, but outside of his body.
In the flame, Cao Yun had used various powders and was controlling several tongues of fire. Slowly, he made his drop of blood float above the furnace. Then, he manipulated each spark of the fire to touch the drop of blood with extreme care. Because he was careful, it took him a long time. But in the end, he put back the blood in his body. The drop of blood touched his chest and seeped through his skin to join his bloodstream.
Then, he analyzed it with a lot of care. Dian Mo was also trying to feel any difference. And the two of them were very pleased to notice that Cao Yun's blood was now even more profound. The properties of the Drop of Wrath were more powerful. The difference wasn't that big but it was clearly there. Besides, it seemed a bit more vibrant and healthy. However, it was also heavier. If Cao Yun made his blood too heavy before his body could deal with it, it would be a problem. Besides, by refining his blood outside of his body, it couldn't adapt to the changes. Thus Cao Yun would need to be careful, even if the results were interesting.
The main thing Cao Yun took out of this experiment though was that he might have a way of helping Hongyu. If Cao Yun could help her refine her blood outside of her body to make it more and more resistant to Evil Qi, her flesh would then slowly gain this property as well. In fact, Hongyu might even become able to use this evil core as she saw fit once her fifth core was fully formed.