Death God: Starting from Refining Essence into Qi

"Detection and Separation of Extraterrestrial Soul Fragments in the Spirit Body".

Xuan's breathing unconsciously slowed, and his fingertips tightened slightly. His identity as a transmigrator was his greatest secret, and the title of this document had struck a nerve with him.

His soul has two parts: one part belongs to this world, and the other part is the soul from his previous life.

He couldn't possibly ignore the scroll that had suddenly appeared, its title clearly stating "Fragment of an Alien Soul".

Xuan suppressed the surging vigilance in his heart, turned to the corresponding index page in the directory, and noted down the number and storage area.

The illusion of all things continued to deceive Tsunemitsu Tetsuhiro's senses. At this moment, Gen had passed through layers of bookshelves and stopped in front of a row of black stone bookshelves labeled "Spiritual Structure - Special Cases".

Xuan manipulated Lingzi to take down the scroll wrapped in dark blue brocade, placed it flat on a stone platform to the side, untied the rope, and slowly unrolled it.

Xuan read it word by word, his brows furrowing deeper and deeper.

The handwriting is neat and cold, carrying an unquestionable academic tone, yet it reveals a chilling cruelty between the lines, truly showing the indifference of treating life as experimental data.

The scroll doesn't explain what "alien soul fragments" are at the beginning; it simply explains the core principle of the detection technology.

The text states that all ordinary spirits, whether Shinigami, Hollows, Quincy, or humans, possess a fixed and uniform density baseline for their souls. Humans have the lowest soul density, followed by Shinigami, while Quincy and Hollows have relatively higher soul densities.

There is a special type of soul fragment whose soul density is tens of thousands of times that of an ordinary human spirit. When it parasitizes a host's soul, it does not completely merge with the host's soul, but only forms an independent, high-density, abnormal region inside the host's soul.

The scroll details the core principles of the detection technology, using precise and restrained language, and consistently employing the term "alien soul fragments."

Xuan's gaze lingered on the scroll. Their souls were tens of thousands of times denser than those of ordinary humans, parasitic yet unable to merge. The Tsunayoshi family had devoted considerable space to researching how to detect and separate them.

The scroll is nominally titled "Fragments of a Different Kind of Soul," but it actually refers to only one thing—a part of the Spirit King. The Tsunayo family deliberately avoided the word "Spirit King," using this vague term to conceal their true research subject.

Xuan understood. The Tsunayo family was the head of the five great noble families, responsible for controlling the Great Spirit Book Corridor, which recorded all the history and secrets of the Soul Society.

They needed to document the technology for future use, but also to ensure that the truth about the dismemberment of the Soul King remained unknown to the public.

The very term "fragment of a different kind of soul" serves as a barrier—only those who already know the truth about the Spirit King will understand its meaning upon seeing this term. To others, it is simply a research paper about rare spiritual anomalies.

Xuan continued reading.

The Tsunayo family conducted extremely detailed anatomical exploration experiments. The results showed that the soul density gradient of all ordinary spirits follows a fixed ratio: the soul density is highest at the location of the soul's sleep, followed by the shackles, then the heart, and then decreases in that order. The density of the limbs is lower than that of the core of the torso, and the soul density of extremities such as nails and hair is the lowest.

Even those special, alien soul fragments, which are part of the Spirit King, follow the same rule in terms of density ratio between their various parts.

Based on this, the Tsunayo family established a complete judgment system.

After recording the soul density of a portion of the Spirit King, they essentially obtained the density reference values ​​for all parts of the Spirit King's body—by measuring the specific soul density of a fragment and then performing a proportional conversion, they could determine which part of the Spirit King it corresponded to.

The following content on the scroll answered many questions that had long existed in Xuan's mind.

Gen finally understood why Aizen Sousuke's subordinates were able to find Matsumoto Rangiku and extract the Soul King's fingernail from her body to present to Aizen. The answer to all of this was hidden within this seemingly ordinary academic document in the Great Spirit Book Corridor.

The scroll then describes in detail the specific operation of the inspection technology.

The core of this technology is called Primordial Spiritual Particle Resonance Scanning, which requires the creation of a probe device using spiritual particles. At the core of the probe is an extremely thin spiritual particle crystal. When spiritual energy passes through the crystal, it emits low-intensity spiritual energy waves toward the target area.

When a spiritual wave comes into contact with a fragment of a different kind of soul, it will resonate and reflect back. By analyzing the frequency and intensity of the reflected wave, the specific soul density of the fragment can be determined. Then, by comparing it with the known density reference values ​​of various parts of a different kind of soul, it can be determined which part of the different kind of soul the fragment belongs to.

A chill ran through Xuan's heart. The Tsunayo family possessed this technology, which meant they essentially had eyes that could see through all the secrets of spirits. Anyone possessing a fragment of a Spirit King within them would have nowhere to hide from them.

However, there was one thing that made Xuan wary: the scroll did not contain the words "Spirit King," but only "Alien Soul."

This technology is specifically designed for a portion of the Soul King, and theoretically shouldn't be able to detect parts of his past life's soul. The past life's soul comes from another world, and the matter that constitutes it has no relation to the Soul Society's spiritual particle system, but the possibility of accidents cannot be completely ruled out.

What if this technology is more sensitive than he imagined, and can even sense souls that do not belong to this world, and treat them as "alien souls"? Wouldn't that lead to him being mistaken for having a part of the Spirit King in his body?

Even more disastrous would be if, after being ambushed and rendered unconscious by the nobles of the Tsunayo family, they discovered that Gen's body did not actually contain a part of the Spirit King.

Xuan tried his best to remain calm and immediately considered countermeasures.

This technology is not demanding on the operator; basic skills in manipulating spiritual particles are sufficient. The intensity of the spiritual energy waves can be adjusted to an extremely low level, so low that the host cannot detect them at all.

Aizen used Kyoka Suigetsu to infiltrate the Great Scripture Corridor, so he must have read this scroll. The fact that even ordinary Shinigami under his command could sense the Soul King's fingernails inside Rangiku's body using creations made with this technology indicates that the technology's principles are clear, its operation is simple, and it is extremely easy to replicate once mastered.

Gen put the scroll back in its place. The illusion of all things being illusory continued to operate steadily. In Tsunayoshi Tetsuhiro's eyes, Gen was no longer flipping through the table of contents, but was seriously recording the Kido.

Xuan made up his mind that he must test himself immediately; if the test results were abnormal, he would take advantage of the time in the Great Spiritual Book Corridor to find a way to cover up the results.

He maintained his ability to make all things illusory while cautiously releasing Zhenyuan. Xuan's already considerable ability to manipulate spirit particles, combined with Zhenyuan's additional enhancement to this ability, allowed him to mold a probe that could be used normally for a short period of time using spirit particles, mimicking the description on the scroll.

A faint light flowed across the probe's surface as it vibrated at an extremely stable frequency. The shaping process required an extremely high degree of precision in manipulating spiritual energy; even the slightest deviation would cause the probe's frequency to deviate from the standard value, resulting in distorted test results.

Fine beads of sweat appeared on Xuan's forehead. He held his breath and adjusted the vibration frequency of the probe little by little until it perfectly matched the standard frequency marked on the reel.

Xuan aimed the probe at himself and began to let the probe collect his information.

The vibration frequency has shifted. It's an extremely weak resonant feedback, but the feedback on the probe is much more pronounced.

The data from various points of the reflected wave converged in Xuan's consciousness, and he quickly used the formula on the scroll, whose principle was unknown, to calculate the specific value. Then he compared this value with the density gradient table provided by the Tsunayo family.

The values ​​in other places are near the upper limit of the Grim Reaper, which is understandable; but there is one place in the center with an astonishingly high soul density: if the soul density of an ordinary human spirit is one unit as recorded on the scroll, then the density of this fragment reaches tens of thousands of units!

This is definitely not the density of a soul from another world!

Startled, Gen used the probe on Tsunayo Tetsuhiro to try and confirm if the probe was malfunctioning.

However, the subsequent feedback from the probe clearly proved that, at least for the time being, the probe was not faulty, and Tsuneya Tetsuhiro's soul density was indeed within the range of a normal Shinigami.

If the probe is correct, then according to the density reference values ​​of various parts of the Spirit King recorded by the Tsunayo family, the astonishingly high value measured by the probe corresponds exactly to the so-called "sleep of a different kind of soul".

Or rather, under the testing standards of the Tsunayo family, it represents the Soul King's soul sleep.

Gen was processing this conclusion, remaining motionless for a long time. It wasn't until Tsunayoshi Tetsuhiro asked Gen if he was troubled by something that Gen suddenly remembered—he had forgotten to update Tsunayoshi Tetsuhiro's feelings. At this moment, the scene he saw showed Gen staring blankly.

After Gen used his ability to make all things illusory to fool Tsunayo Tetsuhiro, who was monitoring him, countless fragments of the past flashed through his mind.

Xuan recalled the few memories his predecessor had before losing consciousness: he was attacked by a Hollow within the Four Maple Inner Palace. Now, considering the allure of the Spirit King fragments, it seemed perfectly normal. He also recalled his extraordinary talent for manipulating spiritual power, which was probably not solely due to the Daoist system. Even though his Zanpakuto, Zhenyuankong, possessed a sword spirit but lacked independent consciousness, its ability to manipulate external spiritual particles far exceeded that of ordinary Shinigami.

Everything has a traceable pattern.

The answer to why Zhenyuan can control external spiritual particles lies here. This ability is something that Shinigami do not possess; it is closer to the talent of Quincy: Shinigami rely on their own spiritual power to fight, Quincy control external spiritual particles, and Zhenyuan can precisely control external spiritual particles like a Quincy.

Because the Soul King's soul was the source of both Quincy and Shinigami power, it possessed characteristics of both Shinigami and Quincy. Through a mysterious and fortuitous encounter, it was born as a sword spirit and ultimately manifested as a Zanpakuto capable of controlling spiritual particles.

While this discovery was unexpected, it wasn't entirely bad. At least the technology couldn't detect his otherworldly soul, meaning his biggest secret was temporarily safe.

The fragments of the Soul King have always been coveted, or rather, guarded against, by the Tsunayoshiro family; they are also coveted material by many ambitious individuals, let alone the Soul King's soul.

If someone uses the same detection technology on Xuan in the future, his secret will be exposed. Therefore, he must hide himself in advance so that he looks no different from an ordinary Grim Reaper when scanned by the probe device.

Xuan slowly spread an extremely thin layer of spiritual particles along the meridians in his body. Zhen Yuan's ability to manipulate spiritual particles allowed him to precisely simulate the soul density distribution curve of an ordinary Shinigami—the soul density of Po Shui was slightly higher than that of the Lock Knot, the Lock Knot was higher than that of the limbs, and so on, decreasing in that order, which was almost identical to the standard gradient recorded by the Tsuna Yayo family.

Since the first probe was formed from spiritual particles, it dissipated shortly after the test. Xuan, with practiced ease, created another probe and conducted a second test on himself.

The spiritual waves flowed smoothly through his body, sweeping over every part. This time, no abnormal resonance occurred. The distribution curve of the soul density values ​​returned by the probe was similar to the standard curve of an ordinary Grim Reaper.

Xuan breathed a sigh of relief and released Zhenyuan from his state. He carefully sensed the situation within his body and found that the simulated distribution of soul density remained stable and would not disappear even after Zhenyuan was released.

This disguise is like a protective film applied to the surface of the soul. It can maintain its existence for a long time by simply sending spiritual energy to it every few hours.

After doing all this, Xuan felt a little more at ease.

He put the scroll back in its place, eliminated his own spiritual energy in the surrounding area, then sat down at the stone table and began to copy down the incantations and release principles of the ghost path.

Xuan originally intended to use the opportunity of recording the Ghost Path to access some hidden knowledge, but he didn't expect to gain such amazing results. However, he had already spent a lot of time on this, and if he didn't finish quickly, it would inevitably arouse suspicion.

Gen quickly finished recording the remaining content and then signaled to Tsunayoshi Tetsuhiro that he had finished.

"You've worked hard, please follow me." Tsunemitsu Tetsuhiro handed the illusionary Zhenyuan back to Gen and led Gen back along the same path.

Stepping out of the Great Spirit Book corridor, it was already completely dark outside. A crescent moon hung in the deep blue sky, its cool light casting a faint silver glow on the stone paths of Seireitei. The heavy, menacing stone protective barrier slowly closed behind them with a muffled thud.

After confirming that there were no other Grim Reapers nearby, Xuan released the illusion of all phenomena.

Xuan looked up at the sky, feeling the cool night breeze. He was calm, feeling neither panic nor excitement at discovering a fragment of the Spirit King within him. He simply had a clearer understanding of his situation and a stronger resolve to follow the path he was determined to take.

Knowing the truth is only the first step. There is still much to be done—mastering the Bankai of both Zanpakuto, balancing the power of the two parts of the soul, and finding the method for stabilizing the soul as described by the saying "All Things Are Illusory".

Of course, they also need to think about how to survive the upcoming war between the Shinigami and the Quincy.

Xuan will not back down, nor will he run away. He will gradually increase his strength and ultimately take control of his own destiny.

After discerning his direction, Gen headed towards the Kidoshu's encampment. The moonlight stretched his shadow longer and longer until it finally disappeared into the Seireitei night.