A sizzling sound was heard as the corrosion on the wall spread out for a few centimeters before stopping. Lin Mu heard the sound and felt shocked at this. He didn't know what had just happened and felt confused at that.

He stood up and walked closer to inspect the wall and saw that a depression about half a centimeter was formed and it was about two inches in diameter. The gas that had touched the wall had dissipated and no traces of it could be seen.

The only thing Lin Mu could sense on the wall was the shallow depression and nothing else.

"What was that Senior Xukong?

" Lin Mu questioned.

"…

"

"Umm, Senior?

" Lin Mu reiterated.

"Hmm, I do not know exactly. It seems to be the impurities being expelled from your body, but they shouldn't be this corrosive.

" Xukong answered.

"What's wrong here?

" Lin Mu asked, feeling more confused.

"You see, by tempering your body, not only do you increase its strength and toughness but also improve its quality. This improvement in quality is brought about by removing the impurities from your body.

" Xukong replied.

"But how do these impurities appear in my body, though?

" Lin Mu questioned.

"They are the result of you consuming sustenance. This can be in any form whether it be food or spirit qi. Everything has faint traces of impurities in them. These impurities slowly accumulate in your body over time and hide within it. For mortals, it does not matter as much, since their life span is not that long, but for cultivators, it is very important as it dictates the improvement in their cultivation and longevity.

" Xukong explained.

Lin Mu finally started to feel like he was understanding it on some level, but he was still confused about the volatility of the impurity that he had just expelled.

"But senior are the impurities really as dangerous as the one from now?

" Lin Mu questioned.

"No, while they can be threatening to a cultivator, that is only in terms of hampering and restricting their cultivation but not actually directly harming them. The gas that you expelled was spirit qi impurity, but it seemed to be corrosive. I do not know the reason for this, but know that it's only good for you since it's being expelled.

" Xukong answered.

"I understand senior.

" Lin Mu replied.

After this, Lin Mu went back to sitting in a cross-legged position on the bed and continued his cultivation session. He closely observed his body and realized that he was already at the border of the twelfth stage of the body tempering realm.

"Senior, I'm already very close to the twelfth stage of the body tempering realm somehow.

" Lin Mu informed.

"I think I can deduce the reason, perhaps. It seems to me that the impurity that you expelled may have been restricting your vital energy from breaking into the next stage. The vital energy within your body kept on being stockpiled and only now when it couldn't store anymore did it breakthrough and pushed you to the border of the twelfth stage of the body tempering realm. That impurity was quite likely the barrier that was restricting you.

" Xukong explained.

"So does this mean that if I want to progress to the next stage, I'll need to expel more of those impurities?

" Lin Mu questioned.

"Yes, that's possible. This will also improve your spirit qi cultivation, in fact. You will soon notice the difference.

" Xukong answered.

Lin Mu inwardly nodded and focused on his cultivation session. He circulated the spirit qi in his meridians and completed a cycle. He then discovered that the speed of his circulation had increased by around thirty percent.

It was as if there were invisible obstructions that he couldn't see before, and now that they were gone he felt free. The spirit qi in his dantian flowed into his meridians and completed a cycle, returning back into the dantian. The cycle thus triggered the fine pores on his body to open up and absorb the ambient spirit qi.

With each subsequent cycle, more and more spirit qi would be added to his dantian. Such was the way of cultivation. In the blink of an eye, it was time for sunset. Lin Mu could not even sense the passage of time, as he was too engrossed in his cultivation.

He only woke up as he was feeling hungry again. In the past few days, he had been restricting his hunger and had been sustaining himself on qi, thus he did not feel hungry back then. But now that he was back to his normal routine, his hunger had returned as well.

Lin Mu thus cooked more spirit beast meat and then ate it. After that, he would assimilate the vital energy from it and once again return to cultivate. Only at midnight would he stop and sleep. Lin Mu had also not slept for the past few days, thus his lessons on the Dao script had fallen behind.

Now that he finally had the chance to learn it again, he didn't want to let it go. He thus laid down on the bed and fell asleep. His consciousness appeared in the Sleepscape, right in front of the spirit apple tree.

Lin Mu looked up and saw twelve spirit apples hanging from the tree.

"Looks like they will continue to accumulate if I don't pick them.

" Lin Mu spoke to himself.

He then walked towards the tree and plucked the twelve apples before storing them in the ring. After that was done, he called out to Senior Xukong for their lessons. He learned the Dao script from senior Xukong for the rest of the night and only stopped when it was time for him to wake up.

Lin Mu repeated this cycle for six days and only paused it when he was called out. The Hei corps member that had been working as a guard outside, Hei Ping had called out to Lin Mu.

Lin Mu walked outside and talked to him. From his conversation, he learned about the current developments and progress in the investigation. He was informed that they had learned nearly no clues from the culprit they had captured.

Since the culprit was a death warrior, he had kept all information to himself and had instead chosen to let himself die. Lin Mu didn't know how he died, but could guess that it was most likely due to torture. He didn't mind that since he knew that they were deserving of it.

Lin Mu was also informed that the first batch of reinforcements had reached the town and more would be coming soon.

"So am I needed there now?

" Lin Mu questioned Hei Ping at the end.

"No. Leader has instead asked that you focus on your cultivation and not to bother with minor matters. She said that she will inform you when something important and deserving of your time happens.

" Hei Ping answered.

After hearing the answered Lin Mu nodded his head and bid the man farewell.

Lin Mu returned to his routine and continued his cultivation for three more days. On the fourth day, a wave of spirit qi spread out from his body. His eyes trembled, but he didn't open them. His chants were echoing in the room now, resonating with the waves of spirit qi.

If one were to look inside Lin Mu's dantian at this time, they would see that it was completely filled with wisps of spirit qi. There was no more space for additional wisps of spirit qi to enter. Right now, Lin Mu was at a very important point in his cultivation.

He was at the very cusp of entering the late stage of the qi refining realm. In order to enter the late stage of the qi refining realm, a cultivator had to completely fill his dantian with the spirit qi and then needed to refine those wisps into a liquid form.

As soon as the first drop of liquid spirit qi was produced, that cultivator would have successfully entered the Late stage of the qi refining realm. But this very step was hard, since refining spirit qi wisps into liquid spirit qi was a volatile process.

One small mistake and the spirit qi could go on a rampage through the cultivator's meridians, causing them harm and regressing their cultivation.

Lin Mu was currently in a deeply focused state. He did not even need to chant the severing heart sutra consciously anymore, as it had become like a second nature to him. His lips would move automatically and the chants would come out of them.

With incredible focus, he circulated more and more of spirit qi through his meridians. He kept on doing it until when finally it had reached a saturation point and his meridians could no longer accommodate more sprite qi.

It was at this point that he kept on pressuring the spirit qi and finally squeezed more in. Bit by bit he kept on adding, and the wisps of spirit qi became smaller and smaller. Eventually, they had become condensed enough to form a small globule.

This small globule flowed through his meridians and finally reached Lin Mu's dantian. As soon as it dropped down into it, another wave of spirit qi spread from his body and spread out in the surroundings.

But this time, the mysterious ring on Lin Mu's hand also started humming along with it. The waves of sprite qi started resonating with the humming of the ring and melded together. It was as if an esoteric harmony was being played and minstrels were singing hymns.

The harmony reached a crescendo, and Lin Mu's body disappeared from the room.