As soon as they entered the valley, within three days, Xiao Hongchen acquired a suitable Soul Ring.
However, the luck of the trio didn't last, and as they delved deeper, they didn't encounter any suitable Soul Beasts for Su Yu.
Not to mention the Ten-thousand-year Sword Grass, they didn't even come across other Soul Beasts with Life Attribute.
The three of them searched tediously in the valley for a month.
Suddenly, Mirror Hongchen pointed in one direction and said, "I sense a considerable fluctuation in Soul Power, restrained yet extremely threatening."
The threat he mentioned was just a sensation, not something that posed a life-threatening danger to him.
The three of them advanced in the direction Mirror Hongchen pointed, and soon, Xiao Hongchen and Su Yu also felt the fluctuation in Soul Power.
"The unique sharpness of this Sword Qi might very well be the Sword Grass." Su Yu said excitedly.
After searching for a month, they finally had a lead.
"Judging by the fluctuation in Soul Power, it's at least a Ten Thousand Years old, though the exact years are unknown."
Mirror Hongchen advised Xiao Hongchen and Su Yu to be cautious, activating their Soul-guided Protective Shields as they continued to explore.
The Soul-guided Protective Shield serves to conceal the fluctuation of Soul Power, which is why they managed to ambush near the battlefield between the Purple Gold Dragon Beast and Silver Moon Tiger for a long time before.
"This Sword Qi is really strong."
Even through the Soul-guided Protective Shield, Su Yu could feel that willpower.
It was a will to cut down everything.
"Seems like it's definitely the Sword Grass, let's hope the years don't exceed twenty thousand."
Su Yu's physique, with regular cultivation and daily body tempering using the Power of the Stars, was likely to reach a level capable of withstanding a Ten-thousand-year Soul Ring by Level 40.
Prior refinement of the Ninth-Grade Snow Lotus had transformed his Martial Soul and physique, increasing the capacity to withstand by three thousand years.
Moreover, Su Yu also refined the Ten-thousand-year Whale Jelly found by Kong Deming, further strengthening his physique and increasing the Soul Ring endurance by at least another three thousand years.
This totaled sixteen thousand years.
Adding Su Yu's self-developed auxiliary methods, increasing by another two thousand years was no problem.
Besides, Su Yu had another external aid.
Which was Ellex.
If he could successfully awaken Ellex during the Soul Ring absorption, the Soul Shock belonging to the Ten-thousand-year Soul Ring would pose no threat to him.
By fully resisting the Soul Power impact and refining the Soul Ring origin, it could invisibly increase the limit by at least four to five thousand years.
Moreover, even if Ellex could not awaken, the simplified version of Red Dust Protection from Mirror Hongchen would still be effective.
The above calculation had already been cautious. Su Yu rounded off the final result conservatively, determining the maximum limit for the fourth Soul Ring to be twenty thousand years.
Although it seemed outrageous, it wasn't hard to understand. The Divine King, with the absorption of Immortal Grass and Ice and Fire Body Refining, still found the absorption of the fourth Soul Ring, which was a Ten-thousand-year Soul Ring, extremely lethal. But that was a direct leap from a two thousand-year Third Ring to over ten thousand years without any groundwork before finding the Ice and Fire Yin Yang Eye.
Yet, Su Yu had started from the Second Ring, absorbing beyond his level, with Innate Life Attribute, tempered by the Power of the Stars in the Second Ring, and refined the Ninth-Grade Snow Lotus for strength equivalent to a Ten-thousand-year Soul Ring, followed by refining a Ten-thousand-year Whale Jelly.
Transitioning from a five thousand eight hundred-year Third Ring to twenty thousand years was actually not so far-fetched.
Especially when considering Su Yu's transition to twenty thousand years, a significant portion was thanks to Ellex or the simplified version of Red Dust Protection.
In this light, setting Su Yu's fourth Soul Ring limit to twenty thousand years seemed reasonable again.
...
"One Main Sword Pattern and five Supporting Sword Patterns, fifteen thousand years!"
Mirror Hongchen finally saw the Sword Grass.
This Ten-thousand-year Sword Grass was not large, only a meter tall, shaped like a long sword, surrounded by Soul Power condensing into white Sword Qi.
The Sword Qi, centered on the Sword Grass, formed a Sword Qi Storm, leaving sword marks on the ground around.
On the Sword Grass's body, there was a silvery white Sword Pattern faintly visible, with one line running from the root to the tip of the Sword Grass, as the Main Sword Pattern.
Surrounding the Main Sword Pattern were five Supporting Sword Patterns.
When ten Supporting Sword Patterns appeared, they would condense into one Main Sword Pattern.
At the Ten-Thousand-Year Soul Beast level, a Supporting Sword Pattern was condensed every thousand years.
Besides the Main and Supporting Sword Patterns, there were other densely interwoven patterns.
"Xiaoyu, what do you think, is it absorbable?" Mirror Hongchen asked Su Yu.
Fifteen thousand years, even higher than the Purple Gold Dragon Beast absorbed by Xiao Hongchen before.
Xiao Hongchen also looked serious, turning to Su Yu, reminding him, "Don't be reckless. I know surpassing a prodigy like me feels accomplished, but a fifteen-thousand-year Soul Ring is very dangerous."
Su Yu's expression was equally heavy, his gaze fixed on the root of the Ten-thousand-year Sword Grass.
"If it were a normal fifteen-thousand-year Sword Grass, I'd have enough confidence, but this sword grass is obviously unusual."
"Oh?"
At Su Yu's reminder, Mirror Hongchen also looked at the root of the Sword Grass and saw the anomaly.
"Mutated Sword Grass!"
The growth of Sword Grass was extremely difficult, with its year count increasing each time it encountered tribulations, thereby condensing Sword Patterns.
To better adapt to such growth, Sword Grass would split into multiple Sword Leaves during growth.
Upon reaching nine leaves, from ninety to a hundred years, nine hundred to a thousand years, nine thousand to ten thousand years, and even ninety thousand to hundred thousand years of transformation, they would unify into nine leaves, overcoming the tribulation.
On one hand, it splits into nine leaves to build depth, waiting to gather stronger power upon breaking through.
On the other, it branches out nine Sword Leaves to provide more hope.
However, the Ten-thousand-year Sword Grass in front of Su Yu showed no trace of splitting or having split leaves at its root!
This was a mutated Sword Grass.
No leaf splitting.
Cutting off all retreats, just one grass, one leaf, overcoming all tribulations.
Undoubtedly, this mutated Sword Grass's individual attack power was more terrifying.
But that's not the issue, as Mirror Hongchen could handle it. Fifteen-thousand-year Sword Grass, no matter how mutated, is still fifteen thousand years.
The problem lies in the difficulty Su Yu would face in absorption.
The Soul Power of a mutated Sword Grass is much harder to refine, with stronger bursts and a more terrifying impact on the meridians.
In other words, the absorption difficulty of this mutated Sword Grass's Soul Ring equates to a twenty-thousand-year two-leaf Sword Grass.
"Xiaoyu, let's find another."
Mirror Hongchen sighed, helpless.
After finally finding a Ten-thousand-year Sword Grass, it turned out to be fifteen thousand years old.
That would have been fine, but it was a mutated Sword Grass.
Unbelievable.
"Wait, Hall Master, I'd like to try."
"What?"
"Su Yu, are you crazy?"
Mirror Hongchen and Xiao Hongchen exclaimed one after the other.
They couldn't fathom why Su Yu, usually so calm and composed, would suddenly be so irrational.
Little did they know, Su Yu was always rational.
In fact, for safety, he had again been conservative in calculating the extreme limit of endurance for the fourth ring.
"Before that, I need to ask, how effective is the simplified version of Red Dust Protection?"