Soon after, Sun Cu's voice came from the communication Gu. "Brother Lin, I've already spent more than a hundred immortal essence stones helping you develop the Flame Path Immortal Gu recipe. I can still provide the immortal materials and Gu materials needed for refining the Immortal Gu later, but you'll have to repay me in the future."
Hearing this, Lin Yan immediately understood.
After spending more time as a Gu Immortal and gradually stabilizing his cultivation, Sun Cu had finally begun to understand just how terrifying the cost of refining Immortal Gu truly was.
Once an Immortal Gu refinement failed, the losses would often be enough to heavily wound even a Gu Immortal's foundation.
Under such circumstances, it was only natural for Sun Cu to begin reconsidering the balance of their alliance.
After all, no Gu Immortal would willingly remain at a disadvantage before a Mortal Gu Master.
However, Lin Yan could still clearly sense Sun Cu's sincerity. The Mortal-grade Flame Path inheritance was one thing, but those two incomplete Rank 6 Immortal Gu recipes were genuinely precious. Depending on their completeness and rarity, their value could range from dozens to even hundreds of immortal essence stones.
After pondering silently for a long while, Lin Yan slowly exhaled. "As long as I can complete Immortal Ascension, the rest can be settled later." He temporarily accepted Sun Cu's conditions before once again immersing himself in the difficult deductions of the Immortal Gu recipe.
This secluded period of deduction lasted a full six months in reality and nearly ten years within the dream realm. Including all his previous research and deductions, Lin Yan had effectively spent almost fifteen years developing this Immortal Gu recipe.
And finally, Lin Yan successfully completed the Immortal Gu recipe for Three Flavors Otherworldly Flame. This was a true self-created Immortal Gu recipe born entirely from Lin Yan's own deductions.
At that moment, countless sparks of inspiration erupted within Lin Yan's mind like a volcanic eruption. His Flame Path attainment surged wildly, directly breaking into the Quasi-Grandmaster level.
Lin Yan's consciousness seemed to enter an indescribable state of enlightenment. Countless ideas continuously emerged within his mind before rapidly becoming complete and clear.
For example, Fiery Sun Explosion Gu, Flame Sparrow Wing Gu, Flame Flash Gu, Hearth God Eye Gu, Blazing Fury Gu, Ever Stronger Gu, Sparks Gu, Fire Thought Gu, Rage Gu, and many other Rank 4 Gu worms.
The Rank 5 refinement recipes for all of them naturally surfaced within his mind. Most of those recipes had already reached seventy to eighty percent completion. With only a small amount of further deduction, they could be fully perfected.
Furthermore, killer moves such as Six-Armed Divine Fire Yama, Rebirth Through Fire, Fury Heart, and Blazing Sun Scorches all revealed far clearer improvement directions within his mind.
"So this is what Quasi-Grandmaster attainment in Flame Path feels like…"
Lin Yan could not help sighing softly in amazement. At this level, creating and improving Flame Path Gu worms had become incomparably natural for him.
As for Gu worms like Fire Thought Gu and Rage Gu, although they technically belonged to Wisdom Path, Lin Yan could still perceive many of their underlying principles through his Flame Path attainment. This was precisely where the profundity of higher attainment levels began to appear.
At the Master level, one gained instinctive understanding and natural control over the Gu worms, killer moves, and refinement methods of their own path.
But after reaching Grandmaster attainment, one's understanding would no longer remain limited to a single path alone. Instead, they could begin drawing connections between different paths, using one path to imitate, understand, or even reproduce the effects of another path.
The most typical examples were Otherworldly Flame Gu. For instance, Sea Heart Flame Gu used Flame Path methods to imitate certain profound mysteries of Water Path, allowing it to resist the natural suppression normally caused by Water Path methods.
Lin Yan was not surprised that his Flame Path attainment had reached the Quasi-Grandmaster level. After all, ever since transmigrating into this world, he had accumulated an enormous foundation over many years. He had spent decades within dream realms researching tirelessly, and recently he had even obtained several Flame Path inheritances along with multiple Flame Path Immortal Gu recipes.
Within the dream realm, he had repeatedly refined every Gu worm recorded in those inheritances, created countless killer moves, and practiced them over and over until many things had already become instinctive to him.
"With this foundation, once I truly refine an Immortal Gu, my Refinement Path attainment will probably also advance to Quasi-Grandmaster."
Even Lin Yan himself could not help feeling somewhat emotional. Mortal Gu Master possessing dual Quasi-Grandmaster attainments was simply shocking.
As for whether any of the Ten Venerables had achieved such a thing during their Mortal life, even Lin Yan himself did not know.
However, in the original novel, there were only two clearly known examples. The first was Fang Yuan, who carried Grandmaster attainment in Blood Path after using Spring Autumn Cicada to return through rebirth.
The second was the future Great Dream Immortal Venerable, Feng Jin Huang. At this point in time, she was still cultivating within Spirit Affinity House, one of Central Continent's Ten Great Ancient Sects, and had yet to fully display her brilliance.
Later, through exploring dream realms, she would obtain Grandmaster attainment in Refinement Path.