Zhao Xing's second-stage treatment hinged on the Transmission Realm Tower.
Bowe believed that the Era of the Barren Domain didn't have any effective method to completely eliminate the True Spirit Heavenly Poison.
But throughout history, many methods had existed that could accomplish exactly that.
Especially certain plants—many of which had already gone extinct in the Barren Domain Era, and the medicinal ingredients from ancient formulas could no longer be found.
There were also plenty of naturally formed sacred lands that had vanished alongside the spread of the Barren Domain.
Take for example the Star-Moon Spring once located in the Valan Barren Domain—it dried up three eras before the Barren Domain emerged. The spring water that used to gather there had been a sacred remedy for healing.
Then there was the Medicine King Realm, which had declined rapidly after the end of the Five Emperors Era. It once held brilliant medical knowledge.
And even some divine objects that had lost their divinity in the present age...
"The Barren Domain Era has nothing,"
"But in the eras before the Barren Domain, there were plenty of methods to cure me," Zhao Xing said, looking down at the list.
"Ji Si, while you were at the Celestial Master Manor, did you ever hear of the Transmission Realm Tower?"
Ji Si was currently pushing Zhao Xing's Floral Armchair. When she heard his question, she immediately nodded.
"I've heard of it. The Transmission Realm Tower is a divine artifact linked to the historian profession. It contains the Daos of Time and Causality. By using it, one can travel to historical eras—and sometimes even bring back treasures from those times."
Zhao Xing asked curiously, "Doesn't that create a paradox? Suppose I go to the Fourth Era before the Barren Domain and take a divine weapon—say, the Grand Derivation Divine Weapon of the Red Star Empire. Wouldn't that mean the Red Star Empire no longer had the weapon from that era onward?"
Ji Si smiled. "You mean, would history itself change?"
Zhao Xing nodded. "Yes. You study both the Fate Officer and Historian Daos. I want to hear your take."
Ji Si thought for a moment and said, "I've read records from the Celestial Master Manor. From what I understand, the time travel enabled by the Transmission Realm Tower must be discussed under multiple scenarios."
"First, true replacement. We can indeed bring back treasures from history. That proves that we're truly entering historical space-times through the tower."
"But it won't let us appear during certain critical historical junctures—like going back to assassinate a Godhood Realm being before their ascension. That's simply not possible."
"As I mentioned earlier, the Transmission Realm Tower is a divine artifact that contains both Time and Causality Daos."
"And because it's a divine object, its power has limits. It can't perform actions beyond its own capacity."
"Also, the Transmission Realm Tower follows an 'equivalent exchange' principle when it comes to retrieving things from the past."
"That is, whether I'm bringing back a Realm Star Dao Weapon or a Reincarnation Dao Weapon, I must provide a weapon of equal tier to swap it out."
"This maintains the 'critical value' between the present and the past."
Zhao Xing seemed to understand. "Critical value—is that kind of like a spiritual energy quota? So the total amount of spiritual energy in the past and present remains unchanged?"
"That's a reasonable way to put it," Ji Si nodded. "But the 'critical value' is actually the Transmission Realm Tower's own metric. It's not simply a matter of exchanging spiritual energy."
"I'm not entirely sure about the specifics either. The Celestial Master Manor doesn't have detailed records."
Following up on the first case, Zhao Xing raised a second question.
"Even if spiritual matter is kept in balance, information is a more elusive thing."
"If we return to the past through the Transmission Realm Tower, wouldn't we still influence it in some way? Like revealing the result of a battle to the humans of the past and changing the outcome."
Ji Si responded, "That touches on the second scenario—the one-way Dao barrier of the Transmission Realm Tower."
"We can retrieve information from the past, but we can't implant our own information into the historical timeline."
"For instance, even if I return to the past and try to write down a cultivation technique for my predecessors, I still can't leave it behind."
"Because techniques embody one's Dao, and my Dao can't possibly surpass the Time and Causality Daos embedded in the Transmission Realm Tower. Therefore, it can't break through the Dao barrier."
"However, if I learn a long-lost cultivation technique from the past, I can bring it back."
"I can obtain the technique—but it won't influence the past in any way."
Zhao Xing asked, "Is the tower's swap function really that precise? Some of the herbs I'll be gathering are extinct. Wouldn't that cause problems?"
Ji Si thought for a moment. "I think the Time and Causality Daos within the Transmission Realm Tower probably shoulder that cost. They smooth out the discrepancies in history."
"From a theoretical standpoint, the treatment plan Bowe set up for you should work."
Ji Si didn't sound very confident—after all, he wasn't a god, and he'd never controlled the Transmission Realm Tower.
Zhao Xing, however, didn't believe the tower could be that perfect. Even if it was a powerful divine object, it couldn't be all-powerful.
If it really were that flawless, then why hadn't Scholar City's ancestors passed it down through the generations?
Why had they buried it deep within the Eighth Scholar Law Realm?
Still, asking Ji Si wouldn't yield answers. Bowe might not even know.
Either way, the journey to the Transmission Realm Tower had already been decided. No matter what doubts he had, it was the only method left that could restore him. Besides, they'd already paid for the treatment.
Before setting out, there was still a lot of preparation to do—namely, mastering history.
Even though Ji Si would accompany him, Zhao Xing's philosophy had always been: relying on others is never as good as relying on yourself.
So he began reading massive amounts of historical materials.
Ji Si, being a Historian, primarily cultivated the profession techniques [Annals], [Ancient Clans], and [Biographies]. These were all related to historical figures and mostly manifested as combat power.
As for [Ten Tables], it recorded major events across the Xuanling Star Domain and provided insight into the Dao of Time.
Among Historian-class cultivators, those who specialized in the Eight Records were ranked the lowest, since they had virtually no combat ability.
The Eight Records mainly covered doctrines, rituals, music, sound theory, star calendars, astronomy, and accounts of diplomacy.
Zhao Xing focused his studies on books related to the Ten Tables and Eight Records, memorizing major environmental changes across time and space in the Xuanling Star Domain, shifts in national borders, and various miscellaneous accounts.
Rustle— Zhao Xing casually picked up a volume titled Tianyou Records of Pacifying Huai.
This book belonged to the category of the Eight Records. Specifically, Tianyou Records of Pacifying Huai documented how the ancient kingdom of Tianyou fought against void rivers and managed disasters within its territory.
Zhao Xing had already read many versions of this book, but different editions from different regions showed different focuses and levels of detail, mostly due to the stylistic preferences of individual historians.
"This one covers the period from the Twenty-Second Era before the Barren Domain to the Twentieth Era before the Barren Domain, lasting 2.4 million Realm Star years."
"That's considered pretty short in terms of historical records," Zhao Xing remarked with interest.
The history of the Xuanling Star Domain could be traced back to the Five Emperors Era. The era of ancient kingdoms only began after the Five Emperors Era ended.
The earliest Ancient Kingdoms emerged around Era Four Hundred, coinciding with the final years of the Five Emperors, during the reign of the Glaze Emperor.
Before that, it was a unified territory under the Five Emperors, and the ancient kingdoms didn't yet exist.
The Glaze Emperor's reign had already been over 400 million Realm Star years ago. The fall of the Five Emperors Era marked the start of the chaotic warring states period of the ancient kingdoms.
So a book covering only two eras was relatively brief—which meant the records would likely be more detailed.
"Tianyou Year Four-Yang 1389, massive upheaval in the Li Star River. A total of 340 million habitable Realm Stars and Star Lands were destroyed by the Li Star River. The disaster of void turbulence affected 3,250 river-adjacent star regions within the Tianyou Ancient Kingdom."
"Huh? The upheaval of Li Star River actually overran more than three thousand star regions? That's a massive catastrophe," Zhao Xing thought.
The rivers within the void layer were flows of condensed "ran"—a form of substance that might be spiritual energy, toxic miasma, or a mix of both.
If it was mostly spiritual energy, with a high stability coefficient, it was called a void river.
If it was mostly harmful and highly chaotic, it was classified as void turbulence.
Normally, the rivers in the Xuanling Star Domain were relatively stable. A massive upheaval like this was quite rare.
The most recent large-scale void river transformation Zhao Xing had encountered was in the Moonfall Mausoleum of the Phantom God Star System, which was washed out by a void river.
But in terms of severity, the Moonfall Mausoleum paled in comparison to what happened with the Li Star River.
"Tianyou Year Four-Yang 1390, forty-six River Generals and Pacification Officers of the affected river zones were executed—"
"Tianyou Year Four-Yang 1423, even after extended management by the Tianyou Grand Shennong Bureau, the Li Star River upheaval could not be subdued. The source of the catastrophe remained undiscovered—"
The Records of Pacifying Huai came with regional maps. Zhao Xing looked closely and saw that the entire southern region of the Tianyou Ancient Kingdom was blacked out—signifying it had vanished.
That meant a large portion of Realm Stars and Star Lands had completely disappeared, turning into a vacuum zone.
Only a few warning markers appeared along the disaster zone's border—some indicated vortexes of violent void wind, others used lightning symbols to show dangerous thunder zones.
Dim starlight marked the less-devastated territories. Even up to Tianyou Year Four-Yang 1550, the situation had not improved—in fact, it had expanded further.
"Didn't expect the Tianyou Ancient Kingdom to have faced such a massive natural disaster in its history." Zhao Xing compared it to a current map of the Tianyou Ancient Kingdom and noticed it was about one-tenth smaller.
The missing region in the south had already been absorbed by the Barren Domain and renamed Li River Barren Domain.
Clearly, that disaster had never been resolved or recovered.
Zhao Xing's curiosity grew.
"Tianyou Ancient Kingdom is one of the top ten among the Ancient Kingdom Alliance, and even they couldn't handle the Li Star River catastrophe?"
"What was the cause?" As a Shennong, Zhao Xing was naturally very curious about any natural calamity.
Especially because the name Tianyou Ancient Kingdom struck a chord with him.
In his altered memories, the previous Xuanling Dao Conference had been hosted by the Tianyou Ancient Kingdom.
Du Yun had become a genius under its banner. Even Zishen Mansion, where Old Qing cultivated before ascending to divinity, had completed its relocation under Tianyou's jurisdiction.
Driven by this curiosity, Zhao Xing kept reading. He didn't discover the answer until halfway through the book.
The upheaval of the Li Star River had lasted an entire era. It wasn't until the end of the Twenty-Second Era before the Barren Domain that the Grand Shennong of the Tianyou Ancient Kingdom finally discovered the cause.
"The source of the Li Star River was located at the Twenty-Ninth Climb of the Dao Manifestation Layer in the northern region of the Tianyou Ancient Kingdom. Grand Shennong Yue Hongdao found a broken branch of an unknown plant species—something never seen before."
"It branches out and spreads. The lower part lies flat on the ancient Dao layer. The lowest segment has unstable roots. The leaves grow opposite each other, either sessile or with very short, stem-clasping petioles."
"The leaf blades are narrowly elliptic to oblong-elliptic, with sharply pointed or blunt tips. The edges have dense, bristle-tipped serrations. The serrated margins are slightly keratinized, gently curved and slightly thickened, and both sides are hairless. The racemes are terminal."
"The flowers grow in pairs, with short pedicels. The bracts are lanceolate, the pedicels are striated and glabrous. The calyx is deeply lobed, the lobes lanceolate and spiny, with membranous edges. The corolla is small, light purple or white—"
"Confirmed through the records of the Primordial Realm, this unknown plant was the legendary Soul-Devouring Grass. Once matured, its combat power rivaled that of a demigod from the human race!"
"It was this plant that kept devouring the deep-void spiritual energy of the Li Star River, pushing the entire river toward becoming a chaos stream…"
"Hiss… such a terrifying natural disaster was actually caused by a legendary plant?" Zhao Xing was stunned. "And it had the strength of a demigod."
Zhao Xing immediately accessed the ancient archives of the Primordial Realm via the star mirror. Unfortunately, the Soul-Devouring Grass had already gone extinct in the river of history.
The last known specimen appeared in the Fifth Era before the Barren Domain, and only a fragment remained as a preserved specimen in today's Primordial Realm.
No living sample remained.
"So many powerful plants must have been born in the long river of history… but so many have also gone extinct," Zhao Xing sighed.
Back in ancient times, the Shennongs of the Self School might not have had as many ultimate techniques as they do now, but their plant-based soldier species were generally much stronger—mainly because acquiring such species back then was vastly different.
Take Zhao Xing's current strongest plant soldier as an example: the Emperor-tier Seven-Region True Spirit Bamboo, a gift from the Five Venom Emperor. But even that was only a seedling.
If it were fully grown, not even the Five Venom Emperor could afford to give it—he didn't have enough himself.
As for legendary species that could rival a demigod, perhaps only Gu Luohe had any.
Plants like the Primordial Divine Tree were god-tier species. They weren't considered battle soldiers, but rather the very foundation of the Primordial Realm.
"With the Transmission Realm Tower reopening, I bet a lot of Shennongs will head to the Primordial Realm," Zhao Xing muttered to himself. "According to the tower's exchange rules, if luck's good, and one encounters an undeveloped legendary seed or sprout, it might only cost a low-grade Samsara Dao weapon, or even just an Origin Divine weapon to bring it back."
"The further back in time you go, the greater the chance of finding powerful plant soldiers."
After all, according to the Self School's cosmology, native species from the Origin Stage and Primordial Stage were definitely stronger than those from the Phenomena Stage. The Phenomena Stage was better suited for the propagation of derivative species.
The reappearance of the Transmission Realm Tower quickly drew widespread attention, even surpassing the heat around Barren Domain development. Countless experts were now planning a journey to the City of Scholars.
And not just historians and Shennongs—other professions were just as eager. Especially those from marginalized classes like musicians and dancers. Who wouldn't want to retrieve lost musical scores or forgotten dances?
Even Great Zhou dispatched envoys back from Wangliang Star Region to Jiachen Pass.
When Zhao Xing was preparing to depart, he learned that Emperor Wu Ji Che, Liu Tianning, and Yun Tiandao were also heading for the City of Scholars to enter the Transmission Realm Tower.
"Fifth Brother, you're going too?" Zhao Xing asked.
"Big Brother, of course I am." Ji Che looked at Zhao Xing sitting on his flower-carved chair with a trace of concern in his eyes. "Ji Si said the Transmission Realm Tower might even lead to the era of the Five Emperors. Of course I want to witness firsthand how the five dynasties of Fortune operated in the Xuanling Star Domain."
"And Brother Yun, you're a Heavenly Timing Shennong. Why are you going?" Zhao Xing turned to Yun Tiandao.
"I mainly want to study historical megadisasters," Yun Tiandao said, pulling out a book from his robes. "Some catastrophic natural events are rare within the current star domains—maybe once every countless years. But inside the Transmission Realm Tower, they're quite common."
He was reading the same Records of Pacifying Huai—his interests surprisingly aligned with Zhao Xing's.
As for his master, Liu Tianning, there was no need to ask. Being from the Self School, his motives were surely the same as most Self School Shennongs.
"Besides that," Yun Tiandao added, "I also want to see what my ancestral homeland looked like in history."
He pointed to a spot on the map of the Xuanling Star Domain.
Everyone's gaze followed—and saw he was pointing to the Shenluo Barren Domain.
Zhao Xing's heart skipped a beat. His curiosity surged once more.
The Shenluo Barren Domain wasn't always barren. So what was the Xuanhuang Realm like in those days?