If the Reverse Flow River were kept outside, it would be fine. But if it was stored inside the Immortal Orifice for a long time, it would consume vast amounts of Heaven and Earth Qi. Once the Heaven and Earth Qi was depleted, the Immortal Orifice would become unstable.
So Fang Yuan had to regularly enter his Immortal Orifice and absorb Heaven and Earth Qi from the outside world to replenish himself.
After absorbing for a while, Fang Yuan closed the gates of his Immortal Orifice.
Walking to the bank of the Reverse Flow River, he was still carrying an Immortal Zombie in his hand.
It was his original physical body.
He tossed the Immortal Zombie body directly into the Reverse Flow River.
The body immediately sank and drifted downstream.
With the help of the Persistence Immortal Gu and the Reverse Flow River, Fang Yuan continuously experimented, trying every method he could think of in succession.
But nothing worked.
"As expected."
"The Soul Path dao marks on the Immortal Zombie body cannot be broken or suppressed by the Reverse Flow River. After all, they are merely dao marks, not Immortal Gu."
"First Transformation to Eighth Transformation Immortal Gu cannot be used inside the Reverse Flow River. But dao marks can still take effect. Just like before, when I hadn't yet conquered the Reverse Flow River, the dao marks on Gu Immortals' bodies still protected them. Eighth Transformation Gu Immortals remained the strongest in the river."
Fang Yuan continued analyzing and identified the reason for his failure.
He had wanted to use the Reverse Flow River to deal with the Soul Path trap on his Immortal Zombie body, but that was impossible.
Fang Yuan wasn't discouraged. In fact, before the experiments, he had already suspected as much.
He placed the Immortal Zombie body back onto Tian Feng Mountain, using the Gu Formation there to seal it once more.
Then he began refining Gu.
A Nightmare Demon Steed's corpse lay before him.
Fang Yuan formed his fingers into a blade and lightly slashed. A golden gleam cut through the air in an instant.
The golden gleam sank into the Nightmare Demon Steed's body and flashed out of existence. The steed's right front leg was immediately severed.
No blood.
After these Nightmare Demon Steeds had fallen in battle, Fang Yuan had the Earth Spirits in his Immortal Orifice perform preliminary processing on the immortal materials. All the blood had been drained from the Nightmare Demon Steeds and collected in one place.
Fang Yuan gave a light tug, separating the right front leg from the horse's body.
Then he spat flames and began processing the severed leg.
Three days later, the right front leg had finally been melted into a mass of purple-black liquid.
Fang Yuan then fed in numerous Gu insects one after another to refine his Gu.
A dozen-odd steps, completed in just a quarter of an hour.
The purple-black liquid erupted in an explosion, and over a hundred mortal dream-path Gu scattered into the air, darting about in all directions.
But with a single thought from Fang Yuan, they all docilely returned to his side.
Over a hundred mortal dream-path Gu!
And that was from just the right front leg of a single Nightmare Demon Steed.
Processing the immortal material had taken the most time. That single step had cost Fang Yuan three days. All the remaining steps combined took only about a quarter of an hour.
This level of efficiency was clearly remarkable, forming a stark contrast with Fang Yuan's previous experience refining Gu inside dreams.
In the dream realm, Fang Yuan first had to gather dream-path materials before refining Gu. Entering dreams carried risk, and sometimes he had to use immortal-level kill moves to break through the dream realm. Refining mortal dream-path Gu required immortal-level kill moves, making the cost quite steep.
But now, with this batch of Nightmare Demon Steeds, his ability to refine mortal dream-path Gu had changed dramatically.
"Just like before, when I used Spring Dream Fruit to refine mortal dream-path Gu, the efficiency improvement was enormous."
"In fact, my refining methods could be further optimized. For example, my previous cutting technique used Gold Path methods, which wasn't an ideal match and wasted some Dream Path dao marks. I could also experiment with other methods for processing immortal materials to see if something more efficient exists."