Han Li originally did not intend to prepare the latter two medicines unrelated to cultivation practice. However, after careful consideration, he felt that no matter how one looked at it, he could be considered half a person of the martial world. Who could say how one day he might face a natural disaster or human calamity? Or how he might become entangled in the constant battles and conflicts of the martial circles? It would surely be wise to prepare some excellent antidotes and healing remedies in advance. Otherwise, should he fall ill or be injured and succumb due to lack of proper medicine, wouldn't that be truly regrettable? Thus, Han Li decided to prepare a modest amount of the latter two medicines to carry with him for unforeseen emergencies. After all, each person's life is only one—Han Li certainly didn't want to die young and premature. Although this would affect the quantities of the other two spiritual medicines and slightly slow down the progress of the cultivation technique, it was ultimately an unavoidable matter. Indeed, no one could expect every single thing to be perfect; in life, one must always make certain compromises. On the very day the elixirs were prepared, Han Li began taking one pill of "Yellow Dragon Elixir" and one of "Golden Essence Pills" according to the instructions specified in the recipe. These two remedies truly lived up to their legendary status; under the powerful and astonishing effects of the medicines, he effortlessly broke through his current limit that very evening and achieved the fourth level of the oral formula. As soon as he reached the fourth floor, Han Li immediately felt a completely different sensation. His five senses surged suddenly into an unprecedented realm. Everything he saw in his eyes became remarkably bright and sharp; details previously invisible to him now appeared magnified and clearly visible—down to the fine strands of spider silk clinging to the corners of the room. His hearing also became astonishingly acute, with countless sounds—both familiar and new—pouring into his ears. For instance, the soft "shushing" sound of a worm burrowing several dozen feet away, or the steady "hum" of an unidentified insect flying past the house—these sounds seemed to resonate directly in his ears, vivid and crisp. In addition, several unexpected odors that had suddenly emerged made him realize that his sense of smell had also undergone a significant transformation. Han Li was both astonished and delighted. This was the first time since practicing this technique that he felt his efforts had not been in vain. Such a unique and distinct experience clearly indicated that the technique was far from useless—it possessed its own distinct merits. While the previous several layers of cultivation had enhanced his five senses to some extent, none had brought about such a profound and transformative change as the fourth layer. This was truly a qualitative leap, as if he had been completely transformed into a new person. In addition, he noticed that his body felt noticeably lighter and more agile, and his mental faculties had made significant progress. Now, even if Han Li went three or five days without sleep, he would hardly experience any strain. He carefully reflected on the entirely different sensations now present within his body. Simply by remaining still, he could clearly perceive all the major and minor events unfolding within a radius of several dozen zhang. This sense of complete control over his surroundings deeply captivated and held him in awe. Now he finally realizes that only at the fourth level does the technique truly begin to show slight mastery. He can't help but recall the unforgettable flavor of the fourth level—what must it be like at the fifth and sixth levels? Just as Han Li had recently grasped the profound essence of his practiced cultivation method, his nominal master, Mo Doctor, returned to the valley. Not only did Mo Doctor return, but he also brought with him a mysterious figure. When Mo Doctor first arrived at Shen Shou Valley, Han Li had already heard the familiar coughing sound from afar, while he was meditating in his stone chamber, striving to advance one more level. Upon sensing Mo Doctor's approach, Han Li promptly finished his meditation and stepped out of the chamber, heading toward the valley entrance to pay his respects to his master, who had not been seen for nearly a year. There, he encountered Mo Doctor not far from the valley entrance. As soon as he saw Mo Doctor, Han Li was taken aback. The man was still the same, yet his complexion now appeared pale and lifeless, with a wan, almost exhausted look. Previously, Han Li had also noticed a yellowish, weak appearance, but never to such a degree of severe decline as this—now he seemed as though his end was near. Even more surprising was the presence behind him: a mysterious figure wearing a black cloak, completely enveloped in a broad green robe, with not a single inch of skin visible. This figure was exceptionally tall and robust, standing at least two heads taller than Han Li, with a towering, divine presence reminiscent of the Giant Spirit God. However, due to the cloak, Han Li could not see the figure's face clearly and only sensed that it must be both grim and grotesquely unattractive. Han Li suppressed his questions and quickly bowed to the doctor, then respectfully stood aside, waiting for the doctor's questions. He was very clear in his mind that the other party didn't really care whether his disciple showed him proper respect or courtesy. Yet, as a disciple, he had to uphold the essential master-disciple etiquette—could not casually neglect it, or risk giving the impression of being unruly, which would only place him in a more disadvantageous position. Based on his understanding of Doctor Mo's usual attentiveness toward his internal cultivation techniques, and considering their prolonged separation, he expected that upon seeing him, Doctor Mo would immediately inquire about the progress of his technique, to assess his current advancement. Indeed, when Doctor Mo saw Han Li approaching from within the valley, he paused slightly, coughed weakly, and then began to ask in a somewhat feeble tone, "How is your technique progressing? Has there been any noticeable improvement?" His face immediately revealed both anxiety and anticipation. Han Li had already mentally prepared for this exchange and delivered his pre-arranged response. "Still much the same, no major changes," Han Li didn't intend to reveal his actual cultivation progress to the other, as he couldn't explain how, without any external assistance, he had suddenly achieved a miraculous leap—from third-level beginner directly to fourth-level. The doctor's expression darkened, and his tone grew firm. Han Li, having carefully observed this shift in the doctor's demeanor, felt a sudden jolt in his chest—his heart subtly uneasy. Yet he wasn't afraid of the doctor personally taking his pulse to examine the condition of his internal qi. Since entering the fourth level, Han Li had unexpectedly discovered that he could freely regulate the strength of his unusual internal qi. He could now control it to match the intensity he had experienced at the third level, thus concealing it completely and avoiding any direct inspection by the doctor.