Fang Yuan found himself transported by the formation to a clear glassy plain. If he didn't know any better, he would've assumed that he had never left the Mushroomman Blessed Land.
However, from this area, he could see a far greater landscape than before. Not only that, above him, his investigative methods detected a Black Heaven beyond the White Heaven seen above, much like with his own aperture.
"Ah! You!" someone shouted out.
It was a Mushroomman Immortal, who was Rank 7. Fang Yuan turned to this person, who was waving his hands, slightly startled. "How did you get here?"
"I was sent here by Paradise Earth Immortal Venerable," Fang Yuan said. "I was sent here as an inheritor."
"Paradise Earth... Inheritor... oh! Oh! I see now!" the Mushroomman Immortal said. "Ah- well then - I'm sorry, could you take a seat here? Let me fetch um, our leader, that's right."
He flew off but then came right back. "Oh, sorry esteemed guest, should I get you something to eat or drink?"
Fang Yuan was nonplussed by the Mushroomman's erratic behavior. He was likely set up as a guard in this area, and had been quite taken aback by Fang Yuan's appearance. Perhaps someone else would've been annoyed or ticked off, but Fang Yuan did not care. He simply waved his hand. "No need to worry about me. I'll wait here for your leader."
"Ah - oh, okay, then," he answered before flying off.
Fang Yuan took a closer look around him and saw that he was in the middle of a vineyard. This vineyard was growing Goose Grapes, so named because of the shape they took. These grapes could grow as large as watermelons, and were filled with Transformation Path dao marks. They were considered to be Rank 6 materials, so this was a relatively valuable area within this place.
Fang Yuan didn't know how long it would be until this 'leader' came, so he chose to take this time to deal with other business.
He didn't have a second to spare!
There were a few things that he had intended to purchase, but for that he needed Immortal Essence Stones.
Much like there were primeval stones, there were also Immortal Essence Stones. However, unlike primeval stones, no Immortal Springs could be found in the world. At least, Fang Yuan had never seen one with his own eyes.
Each Immortal Essence Stone was manufactured by the Heavenly Court - though as to how they did so remained a mystery. The Heavenly Court manufactured them and distributed them to their members and the Ten Ancient Sects, and from there they were passed around the world as a form of currency for Gu Immortals.
Much like with primeval essence, one could not use another person's Immortal Essence with a few exceptions such as with Gu Houses.
However, Immortal Essence Stones could be converted into a drop of Grape Green Immortal Essence. Each stone was worth one bead - because of this, at higher ranks, their value plummeted. At Rank 8, one bead of White Litchi Immortal Essence was worth 10,000 beads of Grape Green Immortal Essence - conversely, one would need 10,000 Immortal Essence Stones in order to make a single bead of White Litchi Immortal Essence.
For Rank 6 and Rank 7 Gu Immortals however, these stones were extraordinarily precious. They could be used to supplement one's Immortal Essence for times of need.
Right now, Fang Yuan's aperture made 2 beads of Grape Green Immortal Essence a day. He couldn't change this into Immortal Essence Stones, however.
The main usage of these stones was for barter and trade on Yellow Treasure Heaven.
Yellow Treasure Heaven was a construct that had emerged in the Medieval Antiquity Era. It was a Grotto-Heaven that belonged to a cultivator by the name of Daoist Countless Treasures. When an aperture reached Rank 8, the Gu Immortal in question could devour a piece of the Immemorial Heavens and fuse them with their aperture.
7 of the Nine Heavens that circled the world had been destroyed by Ren Zu and his children, with only Black Heaven and White Heaven remaining which alternated between each other to create day and night, respectively.
However, fragments of them still existed in this world. If a Grotto-Heaven absorbed one of these fragments, it would no longer undergo calamities or tribulations! However, this came with a major drawback: the Grotto-Heaven in question could not communicate with the outside world through ordinary means.
The Gu Immortal in question who did so would become trapped within their Grotto-Heaven and it could no longer be moved. Additionally, they would need to continue devouring fragments of the Heavens in order to maintain their apertures.
Yellow Treasure Heaven was such a world that had consumed a fragment of Yellow Heaven - Daoist Countless Treasures had long since passed away, and it was controlled by a Land Spirit.
Yellow Treasure Heaven now functioned as a marketplace for trading goods between Gu Immortals. So long as one had the required gu worms to connect to Yellow Treasure Heaven, they could transact things between each other with anonymity. It was similar to online marketplaces back on Earth, though there was the benefit of absolute anonymity. Immortals would send their Wills into the marketplace, and could name themselves whatsoever they wished.
Some people made their identities clear on Yellow Treasure Heaven - this had some benefits as it showed one's sincerity and that they would not run away from a business transaction. Many people also simply had nothing to hide.
Others, such as Demonic Cultivators and Variant Human Cultivators, would naturally keep their identity a secret.
The best part though was that one did not need to commit to either of these paths. One could create multiple Wills, some of them overt and others covert.
As for the location of Yellow Treasure Heaven in the gu world, it had remained a mystery even 500 years into the future. Not even the Heavenly Court or the Venerables had been able to locate it. The Land Spirit in question was also quite firm in its stance - stating multiple times that it would prefer to detonate all of Yellow Treasure Heaven rather than yield, making anyone trying to bully it quite helpless.
It was easy to understand why one would want access to Yellow Treasure Heaven. It took a processing fee for every single transaction, as such, the area within was immeasurably rich. It might even have more wealth than the Heavenly Court itself; some speculated simply from the volume of trade that went through it.
Greater than that though was the chance to monitor trades throughout the world. Although people wished to remain anonymous, it was clear that the Land Spirit knew who was making those deals. It had never divulged this information in all of recorded history, though if one became its master, they would be able to have access to all of this information!
The Heavenly Court would give a massive fee for this kind of invaluable intelligence network, but even the greatest of Wisdom Path Gu Immortals had been unable to deduce its location.
There was a rumor floating around at some point that Yellow Treasure Heaven was actually the creation of Thieving Heaven Demonic Venerable. The reasoning behind such was rather flimsy but essentially boiled down to 'taxes are the greatest form of theft' and that 'there would be no easier way to steal things than to establish Yellow Treasure Heaven.' There was also the fact that Thieving Heaven Demonic Venerable delved into the Space Path and would've had excellent ways of ensuring a Grotto-Heaven remained undetected. This however, was also rather flimsy as there were countless Variant Human Grotto-Heavens that remained undetected to this day as well despite efforts by the Heavenly Court.
As it was, the timeline didn't really fit together for Thieving Heaven to be the originator of Yellow Treasure Heaven, and so Fang Yuan ultimately did not give much credence to this theory.