Because he was extremely careful, it took Cao Yun around an hour to dig deep enough to get to the tunnels under the bloody prairie. However, what he found was a rock he recognized quickly. This was Muddy Granite, a stone that was often used to build sturdy buildings. It was very expensive but it had a high durability. Of course, with Cao Yun's strength, it would be easy to simply pierce through it.
What stayed Cao Yun's hand was just the structure itself. He wanted to get inside those tunnels, not collapse them. Instead of forcing his way through, he put both his hands on the Muddy Granite and sent his Qi within. There were more layers of rock than he had first imagined. Those demonic cultivators had probably spent centuries slowly building these tunnels without being noticed. In a sense, Cao Yun admired their perseverance. Many generations of disciples had died before they could see it complete.
But he had no pity for demonic cultivators in him. He would destroy it himself if he was certain there was nothing to be found within those tunnels.
Finally, he got a clear idea of the general structure of those tunnels. Although he wasn't an architect, he had read books on it. Thankfully, these tunnels were not highly complex. After all, they had been forced to dig them and consolidate them in secret so they didn't use fancy techniques. They tried to make something that was solid and durable, that was it. And they had succeeded so well that Cao Yun could break through the stones here without worry.
Thus he did!
With a single strike from his spear, he destroyed several layers of rocks and jumped down below. He was now in tunnels that were completely dark. Although he could use his Qi to orientate himself, he had no spiritual senses. A Spirit Warrior could see in the dark through his soul. For example, Xiao Xuefeng did not need to use her eyes to see. But Cao Yun had also thought about that after being forced to travel under the mountain in the Yellow Death World.
From his spatial ring, he took out a small rock that was luminescent. The light was very faint and it would not have helped a mere mortal. For Cao Yun though, this was enough to make him see as though in daylight. The tunnels around him were rather spacious compared with what he had imagined at first. Three men could have walked side by side and he still had a bit of space above his head. Even Ren Chao could have walked through there without crouching.
From what he had sensed, this part was only a corridor leading deeper underground. So he simply walked forward, hoping to find a few rooms at some point. Soon, he saw that there were engravings on the walls here and there, probably marks to orientate themselves. At first he wasn't sure how to use them, but he suddenly understood what they were. They were characters combining Nuhua and Moshenhua. Ironically, it reminded him of his problem with Cleansed Asura's documents mixing two languages together.
This time though, Cao Yun was able to speak both Nuhua and Moshenhua. If worse came to worst, Dian Mo was also very well versed in Moshenhua. Of course, Cao Yun was not sure if he would help. But his curiosity would probably get the better of him yet once again.
"Have you understood those characters yet?"
"What?"
Dian Mo had not been observing for quite some time. Watching Cao Yun dig a hole had been extremely boring. And he didn't really like narrow spaces. Instead of looking at walls, Dian Mo had been watching Cao Yun's sea of consciousness. He had almost seen everything now but he had nothing better to do.
"On these walls, you still haven't understood what those strange runes mean? I thought you would have solved them way ahead of me..."
"No need to try and manipulate me. This is childish..." Dian Mo paused for a bit. "Let me see!"
Suddenly he used Cao Yun's eyes to see the runes on the walls.
"Of course, those are directions to know where the rooms are. Just looking at them is enough to understand them, there's nothing to boast about. You should go to the left there. I think the chambers of the sect leader are on that side. But the general library should be on the right. However, I doubt demonic cultivators let their disciples have access to a lot of interesting books..."
"Indeed, my thoughts exactly."
Cao Yun followed the instructions on the walls to advance through the tunnels that turned into some kind of labyrinth. Even with spiritual senses, it would be easy to get lost down here. At some point, Cao Yun took out his compass because he had a bad feeling. And he was right, there were array formations here and there. Some were indicated by the runes but others were completely hidden. Thankfully, Cao Yun was able to feel any trace of Evil Qi.
Even Spirit Warriors would be careful not to expand their spiritual senses too far with Evil Qi in the air. So that was a good way to hide array formations. But this wasn't a problem at all for Cao Yun and the intent of the Drop of Wrath. Both Dian Mo and Cao Yun found this expedition boring. These tunnels had been made to be welcoming to demonic cultivators and hostile to orthodox ones. Given Cao Yun's ability, those tunnels turned out to be very friendly to him.
He was forced to find new paths though. The 5th Imperial Brocade Guards had collapsed some tunnels all over the place. However, there were no corpses at all. They had probably taken all the corpses out to burn them at one go. According to what he had heard from Xiao Xuefeng, the Wolf Head Sect's Sect Leader had been a 4th-grade Spirit Warrior. Compared with Cao Yun, this was extremely high, but overall, considering the major powers of the Hongchen Kingdom, this was nothing impressive. Even Cao Beiwen had reached 6th-grade Spirit Warrior and he was only 213 years old.
Besides, demonic cultivators were supposed to be faster than orthodox cultivators. Either this one had been stuck for a long time or he was younger than 200 years old. There was no way he was the one who had lead the attack on the Cao family. But he might have had some useful information anyway. Unfortunately he had been killed. The next best thing would be to investigate his chambers and his study.
At last, Cao Yun reached the room he had been looking for. Before entering, he studied the door and the vicinity of it. There might be traps either to kill intruders or even to take care of other disciples. Demonic cultivators were not very trustworthy in general. The Sect Leader would have probably been paranoid about his own disciples, and he would have been right to be.
Just as he thought, Cao Yun discovered a few traps as well as some array formations all around the door and inside the room itself. Taking out his compass, he began to solve them. In his sea of consciousness, Dian Mo was getting more and more bored.
After two hours, Dian Mo reached the end of his patience. One could have thought that such an old spirit who had lived millenniums in seclusion would be more patient, but it was the opposite. Dian Mo had consumed all of his patience already.
"Do what I say. Those array formations are really rudimentary. Not one of them can reach the apex. And yet, here you are taking your sweet time with them. If I don't act now, we'll be there for weeks..."
Cao Yun did not try to argue. He knew this wasn't a trap coming from Dian Mo. The more time he was spending with him, the more he realized that he might be able to find some common ground with him. Although he had been created by Demon God Da Mo, he didn't seem to be as violent and tyrannical as his master. Of course, he had no body for now. If he were to become a powerful cultivator, he might show his true colors. So Cao Yun could not trust him completely. However, he could trust his sincere curiosity with everything around him.
Finally, all the traps were disposed of and Cao Yun entered the room.
As soon as he did, he felt a cold feeling in his spine. It was very faint, so faint that no one would have noticed it but him. However, Cao Yun had worked on Death Energy, on 'Death Verses' and on his own soul. This wasn't Death Energy, nor was it related to Evil Qi or to Po. No, this time, he felt a sensation that reminded him of his Hun the Wood Ethereal Soul. Thus, the very first thought that came to Cao Yun's mind was the presence of a ghost.
His very first instinct was to immediately dash out of the room but he controlled himself. This sensation had been so tame that it was clearly not an attack. Apart from a middle to late Spirit Warrior, no cultivator should have been able to sense it. After all, Mortals and Mortal Warriors were not supposed to be able to enter their sea of consciousness and feel their very soul. Even if they had felt that cold, they would not have made any connection between this and a possible ghost.
Cao Yun wasn't absolutely sure but there was a ghost or something similar in this room. For now, it was studying Cao Yun. On the other hand, Cao Yun had no way of studying the ghost. Although he had felt that, he had no way of sending his soul outside to try and track the source of this sensation. Only a Spirit Warrior could do something like that. This was one of the reasons why ghosts were so terrifying. They could attack someone's soul and only a Spirit Warrior could protect against that.
Thankfully, ghosts were weak to Yang. Sometimes, the sun itself was enough to destroy them if they were weak enough.
Using his Chamber of Heavenly Court to think about it a long time, Cao Yun decided to act as if he had felt nothing. He had no fear of a ghost trying to attack his soul. Besides his Drop of Wrath, he knew that even Dian Mo would defend him because he couldn't afford to lose his body to someone else. Thus, Cao Yun adopted the same attitude he had used against Dian Mo, he would bait this ghost.
With this train of thought, Cao Yun began to observe the room. There were a few books but not many. The most likely hypothesis was that the Sect Leader had kept most of his important documents inside his spatial ring. That meant that it had probably been taken away by the 5th Imperial Brocade Guards. In that case, that would really be a loss for Cao Yun. The books he found were absolutely not interesting at all. Most of them were not even demonic arts. One of the books was literally a book about architecture. Another one was talking about the general politics of a martial sect.
Still, this room made Cao Yun doubtful. There had been too many traps just for that. Even if the Sect Leader was paranoid about being betrayed and killed, this was too much. As a 4th-grade Spirit Warrior, he barely had to sleep, eat or drink. It was almost impossible to attack him by surprise in this room which was deep within the tunnels. So Cao Yun was forced to believe that there was something more to find.
Expanding his Qi outward, he found that there was Evil Qi in the walls to try and prevent people to send their spiritual senses beyond. Of course, that did not apply to Cao Yun who had no spiritual senses. But he had the Drop of Wrath. And it proved him right, there was another room hidden beneath this one. As it was rather small, it certainly only contained the important documents. With just his Qi, Cao Yun could not know. He could only sense that there was an empty space there thanks to the Evil Qi around the place. But he had no spiritual senses to really see what was beyond that wall.
Sifting through the room, he finally found some mechanism to open a trap. He could have burst it open but he didn't want to give away that he had felt this space to the ghost observing him.
In that tiny space, there were indeed many documents, all handwritten. But the writings were different. Several people had written those various texts. And they were all written in that strange language he had seen on the walls, mixing Nuhua and Moshenhua. Even without Dian Mo's help, Cao Yun could read them, but his help would make the process smoother and faster.
When Cao Yun took the documents and put them on the desk, only then, did the ghost attack.
All of a sudden, Cao Yun felt a deep cold envelop his entire body. It lasted only an instant. Then, some outside force tried to penetrate his Bai Hui. Panicked, Cao Yun tried to flail about. Absolute horror was filling his eyes. The young man had no idea what was going on!
The ghost who had attacked him was very pleased with this reaction. He had been quite worried after seeing the boy take care of his array formations so easily. But he was just a kid after all. Some higher demonic cultivator had probably told him how to get in there. Now that his body was dead, it seemed that everybody had forsaken him...
This ghost wasn't a ghost yet, he was Lang Shou, the Wolf Head Sect's Sect Leader. During the raid of the 5th Imperial Brocade Guards, his body had been killed. They had even attacked his Soul Embryo and had thought they had killed it too. Thankfully, Lang Shou had been able to extract the soul of one of his disciples. He had used it as a decoy to make them believe in his death. Since then though, he had been confined in this place.
With the wounds he had sustained and without his body, Lang Shou's Soul Embryo was slowly dying out. As a 4th-grade Spirit Warrior, his soul had not even been inside his Soul Embryo to begin with. At the very last moment, he had forced his soul inside. He knew that this would cause great damage to his Soul Embryo, but it was the only way to avoid death back then.
Hopefully, he might be able to use this boy's body to get to the Demon King. He might have a way to help him. Or he might just kill him. Lang Shou had no other choice anyway.