The text that marked Cao Yun the most was indeed the 'Universal Law of Immortality'. In the complete version, the first three realms were unchanged. Cao Yun read nothing new. But then, there were other entries.
The Sage realm was also known as the Dao Realm. During this realm, the cultivator would slowly transform his sea of consciousness into an inner world. Each grade consisted in furthering this transformation. At first, a pagoda would appear and it would gain one floor by grade. The more he read about this realm, the more Cao Yun thought about the Yellow Death World. That dimension had literally been the sea of consciousness of Cleansed Asura. As a God-Monarch, he had of course gone through those nine grades and beyond.
Within this realm, it was possible to absorb treasures from the physical world in order to help strengthen one's inner world. That was probably why Cleansed Asura had taken the seed of the world tree. But then, Cao Yun also had a small seed of the world tree in him. A part of it had been used to help heal his Bai Hui, but he could still feel the seed asleep in his sea of consciousness. Maybe it would be useful to him once he became a Sage. For Cao Yun, there was no doubt that he would become a Sage in the future.
Mo Tian's goal had been to merge human cultivation and demon cultivation. Ironically, Cao Yun who had helped thwart his plan had achieved this without even trying to. Thanks to the Drop of Wrath, Cao Yun could practice the blood cultivation of demons while keeping a human body.
During the Sage realm, one would finally be able to see through the Dao. Thus, a Sage would try to learn as many smaller Dao as possible. Although it was technically possible to break through without ever studying the Dao, it would then prevent the cultivator from reaching the highest realms of cultivation. The Sage realm was the perfect realm to study the Dao. As such, it was advised to not rush it at all. However, the Sage realm did not offer any gain in longevity. And it could take a couple of centuries to go through it, even for someone who was rushing it and didn't care about having a firm and stable cultivation.
Then, the Monarch realm, also known as the Domain Realm, consisted in tempering this inner world into a Domain that could be manifested in the physical world. It was way more dangerous. Just like the Sage realm, it did not offer any gain in longevity. And as it was dangerous, it was advised not to rush it either. Besides, once a Domain was forged, it was almost impossible to change it. Considering how powerful and important a Domain was, it was better to forge the best Domain possible.
After those two realms was finally the Immortal realm, also known as the Fusion Realm. In this realm, the physical body and the Soul Embryo would slowly fuse. Once again, it was a very dangerous realm as both the physical body and the Soul Embryo could be damaged by a careless cultivator. However, each grade offered great gains in longevity. Instead of living two millenniums, a 1st-grade Immortal could leave five millenniums. And a 9th-grade Immortal could even reach the age of fifty thousand years. By fusing the physical body and the Soul Embryo, an Immortal would develop an Immortal Body that would not need any form of sustenance apart from pure energy.
Concerning the later realms of God, God-Monarch and Dao, there was almost nothing. Cao Yun only understood that a God had to harmonize with his universe. Then, a God-Monarch would have to leave his universe, to cross the veil between the worlds and explore other universes. That was what Cleansed Asura had done. Finally, the Dao realm was clouded in mystery. But the end goal was to go back to the origin of all things, the Dao itself.
Of course, Emperor Nuwa had written this 'Universal Law of Immortality' before ascending. As such, she had been a Sage or an early Monarch at the time. Thus, her understanding of the higher realms was shallow at best. The mere fact that she had been able to get a sense of what they were was impressive in itself.
Despite his speed, it took Cao Yun a couple of days to read everything. As per their agreement, he couldn't have hidden everything from Dian Mo. Indeed, he could only block his senses during two double hours every day. In fact, recently, he had barely used this. But according to their agreement, he couldn't accumulate those hours. If he didn't block his senses in a day, those two double hours were lost forever.
Cao Yun had decided to be way more selective with what he hid from Dian Mo. Despite the threat he was posing, Dian Mo was also a great source of information. Although he was not willing to divulge everything, he was also unable to control his mouth. Dian Mo had to talk to someone about almost anything. Most of the times though, it was to complain that the current era sucked and that humans and demons alike were pathetic. He could go on a rant for days if no one stopped him. Sometimes Cao Yun let him speak alone until he was satisfied.
Although he couldn't cut off Dian Mo's perception of the outside world, he could cut off his own perception of Dian Mo. Since he was in his sea of consciousness, this was just like a voice in his head. Because he could control his thoughts, he could also control Dian Mo's voice and make it so quiet he couldn't hear it, just know that it was there, still speaking.
Dian Mo had read the integral 'Universal Law of Immortality'. Since it had been written by Emperor Nuwa after the defeat of Demon God Da Mo, he had had no way of knowing about it before.
"That Nuwa brat... Even as a slave, she was impressive... I hate to admit it but she was probably smarter than Demon God Da Mo..."
This was the first time Dian Mo acknowledged a human. Even though he wanted Cao Yun's body, he had never praised him. Because he had been created by Demon God Da Mo, of course he had a prejudice against humans. But demons didn't fare any better in his views. Only Demon God Da Mo was above everyone else, and Dian Mo thought himself superior to them as well. Even defeated by Cao Yun, he put the blame on the Drop of Wrath that was abnormal, not on Cao Yun himself. As such, he could keep his pride.
But now that he was looking at what Emperor Nuwa had written, he was forced to admit that she was talented. Even using the word 'brat' was an improvement for him.
"Of course, she probably swarmed Demon God Da Mo with numbers to win against him. But she was not as bad as I thought she was. When you look at this cultivation though, there are some similarities with the cultivation of asura. They're not obvious at first, but they are here, just like your mind cultivation is similar to the Accomplished Demon realm. Most likely, it stems from the fact that asura and humans share a common ancestor. I'm sure that deva cultivation would also have some similarities.
"Look, for example, humans create a Soul Embryo while asura forge a Demon Soul. Since each one is different, they require different forms of cultivation of course, but the general idea is the same. You need this new form of soul to reach immortality afterward. And during the Immortal Demon realm, the equivalent of the Immortal realm, the asura merges his spirit with the Demon Soul in every drop of his own blood. This is very similar to what humans do by merging their physical body with their Soul Embryo.
"Even a Domain is not unlike the True Fire of asura. An Exalted Demon can't fight a Reborn Demon because they control the True Fire that can burn through everything. The very blood of a Reborn Demon is so potent and powerful that it's almost impossible for someone under this realm to fight them. I've never heard of a Monarch fighting a Reborn Demon, but I suspect that a Domain and the True Fire are somewhat on the same level."
Dian Mo gave a lot of information concerning the blood cultivation of asura and demons. But Cao Yun had already read about it in the 'Crimson Inferno Road'. Unlike the 'Universal Law of Cultivation', it had been complete from the beginning. However, the last realms were also really cryptic, probably because Demon God Da Mo himself wasn't too sure about those either. After all, not many cultivators could have reached such realms.
Since Dian Mo was in a talking mood, which happened very often to be honest, Cao Yun decided to entertain him. And he began to talk in depths about the human cultivation and the asura cultivation.
At first, Dian Mo was not impressed by Cao Yun's conversation. But as he listened to the boy, he realized that he had a more thorough comprehension than what he had believed. In fact, both Dian Mo and Cao Yun got really into the conversation. They also discussed about the 'Sealing the Seven Demons in the Nine Peaks' and 'Storms in the Crimson Furnace' manuals.
The first one was probably the work of a demon trying to imitate humans in order to produce something closer to a Soul Embryo, instead of a normal Demon Soul. On the other hand, the blood cultivation he had received from Matriarch Huang, was the attempt at copying the demons' blood cultivation. Apparently, whoever had created this method had also observed demonic beasts to fill some holes in his understanding.
As they were talking, Cao Yun learned a lot about blood cultivation that might help him in the future. Although Dian Mo was not willing to help Cao Yun without any compensation, he was just too engrossed in the conversation. Of course, he was not stupid and knew that Cao Yun was getting more out of it than he was. But he couldn't deny that he loved talking. And as a matter of fact, he loved talking with such an interesting boy.
Similarly, Cao Yun who was passionate about discovering new martial arts and new cultivation methods, found their discussion entertaining and captivating. Not only was it helpful for his future, it was also a delight in itself.
"I'm pleased to see that blood cultivation fascinates you so much, but I have a question for you."
"Go ahead, you've never asked my permission before."
"What about your Qi cultivation? Although I can't sense it well enough, your Bai Hui should be mostly healed by now. No one seems to know exactly what happened, but my guess is that you have some idea about it... I won't ask you what healed your Bai Hui but I know this wasn't the Drop of Wrath or your blood and I have no idea what that seed or that vine were. That being said, that physician told you that it was fine to use your Bai Hui now. Even during the fight with that girl, you used it at full capacity.
"Yet, you've not once worked on your Qi cultivation, as though you were afraid of damaging your Bai Hui once again. At your level, the blood cultivation won't let you become stronger fast. After all, your current blood cultivation is already very advanced. Of course, it's unstable and starting from scratch is a good idea indeed. Practicing from the Blood Child realm will stabilize your blood cultivation and allow you to go to higher peaks later. However, it won't replace your Qi cultivation for a long time."
That was a question that had plagued Cao Yun as well.
"If my Bai Hui is damaged, it's because of you!"
"Oh...? Yes, I'm truly sorry about that... It's not as though I had paid for it by being trapped and tortured into your mind."
Cao Yun disregarded the clear mockery in Dian Mo's words. However, he was really struggling with that question. And since he had been talking with Dian Mo for so long, it now felt natural to discuss his problems as well. Dian Mo was not the only one who was too talkative apparently.
"The truth is that I'm not too sure what happened to my Bai Hui either. Right now, it seems weaker than my other Prodigious Gates, but it is also full of vitality. When I first used the Drop of Wrath, I had no idea what it was but I was following a manual that made sense. Now, I know what this seed was but I have no idea what I should do with it. Even now, I can feel that it's still asleep within my sea of consciousness even if I can't see it directly.
"To be honest, I'm afraid of hurting myself even more. For now, the wound seems healed, but it could come back with a vengeance if I do whatever with my Bai Hui. I know that I should get back to cultivating my Qi, but I feel anxious about it. Yes, I could use my mind cultivation to push it aside. But that could also cause me to be too reckless. I need to have a clear mind without worry when I cultivate, especially after what happened to my Bai Hui because of YOU."
"Come on... I was trying to deceive you, you were trying to deceive me. And you won at the end. I should be the one being angry with you. But look at me, I'm being the bigger spirit here."
After that witticism by Dian Mo, there was an awkward pause.
"About your Bai Hui, boy, the more you wait before cultivating it again, the harder it will get. In fact, you might even develop an inner demon because of it. I know your mind cultivation is powerful, but you have to be proactive as well."
"And why do you care so much about my well-being?"
"Simple. If you die, I die. And you're going to go against people who could kill you just with a slap of their hand. Against Mortal Warriors, I don't think you can lose unless they're too many. However, the weakest of Spirit Warriors could eliminate you with a thought. Unless you trap them by luring them into your mind like you did to me, you can't win, you can just run away."
"I know... But I also know that Sect Leader Xuan will never let me leave without some form of protection. But if you really want to help keep me alive, you might talk about the seals used by demonic cultivators."