How the Rotten Mud Gang incident would ultimately unfold remained unknown to Ren Qing. However, he received the mission reward the very next day.
He had expected the compensation to be delivered by the Nether Crow, as Huang Ziwang mentioned. Instead, it was Muyi who arrived.
The reason was that Song Zongwu was temporarily occupied and couldn't break free, so he entrusted Muyi to explain the details about Blood Crystals to Ren Qing.
This showed that Song Zongwu still kept an eye on Ren Qing's activities.
After Muyi's explanation, Ren Qing understood why the Restraint Officers' Hall used Blood Crystals as currency.
First, they were extremely portable.
When exposed to high heat, Blood Crystals would liquefy and merge together.
After merging, the Blood Crystal's size remained unchanged, only its color deepened and it's weight increased.
Ren Qing split a Blood Crystal in half, and the fragments quickly reformed into teardrop shapes, their total weight identical to one another.
This meant there was virtually no loss.
Thus, weight became the standard for assessing value.
A Blood Crystal weighing around one catty was called a "Sheng." Ten catties made a "Dou," and a hundred catties was a "Shi."
This weight-based system had been in use for a long time, not just in the Restraint Officers' Hall, but also among ordinary people. It was said to date back over a thousand years.
Ren Qing found this deeply puzzling.
As far as he could tell, Sanxiang City had no historical records whatsoever. No one knew which dynasty they lived under, yet everyone simply took it for granted.
To avoid seeming suspicious, Ren Qing never inquired about the erased history, which likely involved the severed northern lands.
He would have to wait until his cultivation reached greater heights before investigating further.
Fortunately, the reward for the Rotten Mud Gang mission was generous, giving Ren Qing hope of achieving his Eerie Transformations soon.
Even though he'd contributed little, the Restraint Officers' Hall still awarded him fifteen Dou of Blood Crystals, one and a half Shi.
A hundred Dou could already be exchanged for a Half-Corpse Realm Supernatural Remnant.
However, for most Restraint Officers, despite the abundance of Supernatural Remnants in the Hall, finding one matching their desired mutation path remained difficult.
So they either spent their Blood Crystals on resources or saved up five hundred Dou to directly exchange for technique manuals.
Ren Qing couldn't help feeling regretful, had he been a reserve during the Disaster-Dispelling Forbidden Zone incident, he might already have acquired a new technique.
He stored the Blood Crystals and the Great Miao Blade in his Prison Within the Abdomen, then spent the next few days cultivating quietly in the Corpse Burners' Hall.
When the Ghost Market was about to open, Huang Ziwang finally arrived, barging into Ren Qing's room under Bo Feng's stunned gaze.
Had Xiao Wu not recognized Huang Ziwang, Bo Feng might have rushed to report him to the authorities.
Ren Qing was already prepared, dressed in his rain cloak and hat.
Huang Ziwang, however, made no effort to conceal his appearance. "Let's go, Little Brother Ren!"
Ren Qing drew a door to the Restraint Officers' Hall with his Bone Key, and the two stepped through one after another. Moments later, the wooden door vanished.
Avici Hell was still drenched in blood rain, but it seemed livelier than before.
From atop the ribs, Ren Qing saw dozens of Restraint Officers heading southeast, far more cultivators than he'd expected at the Ghost Market.
Huang Ziwang explained, "The Ghost Market is where you exchange resources. If you're free each month, you can come."
Ren Qing asked curiously, "Are there Restraint Officers from beyond Xiangxiang?"
Huang Ziwang replied softly, "With so many uncharted Forbidden Zones around Xiangxiang, the Restraint Officers' Hall forbids us from leaving."
He paused, then added, "Song Zongwu has definitely left Xiangxiang before. You could try probing him."
Ren Qing shook his head. Song Zongwu was tight-lipped about such matters, no chance he'd talk.
But he had his suspicions.
Ren Qing theorized that southern lands had fewer Forbidden Zones, hence the ban on Restraint Officers, carriers of Supernatural Remnants venturing there.
Xiangxiang might be a buffer zone straddling north and south.
While the north had already fallen completely.
Huang Ziwang led Ren Qing across a long stretch of land until they reached a southeastern clearing, then sat in a nearby grove.
Dozens of Restraint Officers had gathered nearby, seemingly waiting for something.
After an indeterminate amount of time, just as Huang Ziwang began yawning drowsily, an excited shout rose from the crowd: "It's here! The Ghost Market!!!"
The ground trembled as faint mist slowly descended.
Even the blood rain couldn't penetrate, as if blocked by some unseen force.
When the mist dissipated, a dreamlike marketplace came into view.
The streets bustled with ethereal pedestrians, countless stalls lining the lanes, the aroma of street food wafting through the air.
The crowd surged forward.
Restraint Officers moved through the streets, their touch reducing passersby to wisps of smoke that quickly reformed.
Following behind, Ren Qing frowned and asked, "Is this a technique?"
Huang Ziwang nodded. "Butterfly Dream Technique."
"Butterfly Dream Technique..."
Ren Qing muttered the name, vaguely recalling seeing it mentioned in the Secret Pavilion, though the records were unclear.
Only one allusion came to mind:
Zhuangzi's Butterfly Dream.
Huang Ziwang said reverently, "This technique belongs to Great Dream True Person, a cultivator at the peak of the Yin Runner Realm."
The Butterfly Dream Technique allowed its user to construct illusory yet tangible dreamscapes while asleep, pulling others into them.
In other words, on the fifteenth of each month, Great Dream True Person would dream a marketplace called the Ghost Market, enabling Restraint Officers to gather and trade.
Ren Qing's expression turned contemplative as the surrounding clamor flooded his ears, the illusory figures feeling eerily real.
An old man at a noodle stall called out to him, "Customer, want a bowl of Yangchun Noodles?"
Before Ren Qing could reply, Huang Ziwang refused on his behalf, "No need, old man."
Ren Qing was startled, were these marketgoers not just illusions?
Huang Ziwang explained, "The food here can indeed be eaten, but while it has flavor, it can't be swallowed."
"Plus, though it costs no silver, rumor says it shortens your lifespan."
"I see."
Ren Qing's eyebrows rose. Could the Butterfly Dream Technique extend life this way?
The dream's rules were likely set by Great Dream True Person, trading lifespan for sustenance seemed plausible.
Ren Qing's spirits lifted. Merely stepping into the Ghost Market had already revealed clues to lifespan-extending techniques.
Yet the market felt nothing like a dream. Every illusion seemed sentient, what if they existed independently of it...?
Suddenly, Ren Qing's expression changed.
Didn't the Rat Mother technique produce similar effects?
Theoratically, opossum clones used for substitution were new lives inheriting memories, more like offspring than copies.
If Tu Di had created such clones... was he searching for an independently conscious... other self?
"Ren Qing, what's wrong?"
Huang Ziwang interrupted his thoughts.
Ren Qing suppressed his speculations. Reporting them to the Restraint Officers' Hall would only invite trouble, it was better to tell Song Zongwu when the chance arose.