Cosmic Trading System

Phew!

With the thought, Lin Yun immediately crossed his legs on the ground, flipped his hand, and sent the remaining gray crystal into his mouth.

"Boom! Boom! Boom!"

The moment the gray crystal entered his mouth, powerful waves of spiritual energy immediately exploded inside Lin Yun's oral cavity, rushing towards the space in his mind, causing his mental strength to rapidly increase like a fire fanned by wind, and at the same time, Lin Yun's mind became exceptionally clear.

"The level of this spiritual energy is so high, it's estimated that it can enhance the mental strength of a second-level Super Warrior cultivator..."

Lin Yun murmured in shock.

Previously, because the amount of gray crystal fragments he consumed was not much, although the spiritual energy they produced was vast and of high level, compared to the mental strength of a second-level Super Warrior cultivator, it was far inferior. It quickly diluted in the space of his mind.

Therefore, he only deduced that the level of spiritual energy was not low and it was absolutely harmless to him, but he did not determine the specific level of this spiritual energy.

Now, he had figured it out.

A treasure that could enhance the mental strength of Super Warriors... or even that of a second-level Super Warrior cultivator's mental strength...

The value of a treasure of this level was immeasurable, far surpassing those Heavenly and Earthly Divine Hearts he had purchased earlier.

Perhaps, only the Super Golden Liquid given to him by Little Gold's mother could compare with this gray crystal.

"Could it be that this gray crystal was left behind by a second-level Ghost Practitioner of the Super Warrior realm?" Lin Yun thought reflectively.

Thinking this, Lin Yun couldn't help but feel a trace of excitement. Doesn't this mean that if he encounters other Ghost Practitioners later, once he kills them, he may also obtain such gray crystals?

And, the stronger the opponent, the higher the grade of gray crystal he could get?

The more he thought about the possibility of encountering a third-level Super Warrior realm Ghost Practitioner at the end... the more excited he became.

However, Lin Yun quickly set aside this thought.

Whether things would turn out this way could be confirmed after he encountered other Ghost Practitioners and killed them. Right now, the most important thing was to properly digest this gray crystal.

"Huff! Huff! Huff!"

Lin Yun closed his eyes and began to quickly refine the gray crystal.

He discovered that the spiritual energy emitted by this gray crystal was very easy to refine, far surpassing the refining speed of Heavenly and Earthly Divine Hearts, which was why he decided to refine this gray crystal on the spot.

Otherwise, with only half a year left to challenge the Heavenly Principle Tower, he feared he would waste most of his time here.

The higher levels of the Heavenly Principle Tower, he was still very curious about what they were like—how could he waste his time here?

One day... two days... three days...

Although the spiritual energy within this gray crystal refined quickly, the amount of spiritual energy it contained was so immense that it took Lin Yun three full days to completely refine it.

"Hum—"

Just as Lin Yun finished refining all the spiritual energy, his mind space suddenly shook, and a mysterious fluctuation emanated from his mental strength. His mental strength began to rapidly evolve.

It was at this moment that his mental strength broke through from the late stages of level twelve to the peak of level twelve.

Indeed, Lin Yun's initial mental strength was at the late stages of level twelve. Although he had already obtained a high-level Heavenly and Earthly Divine Heart from the Eastern Emperor, which was enough to elevate his mental strength to the peak of level twelve, refining the Divine Heart took quite some time.

He had not had the chance to extensively refine those Divine Hearts.

His mental strength had only reached a not-weak level of the late stages of level twelve.

This time, however, in just three days, his mental strength advanced to the peak of level twelve, which indeed could not be compared with refining Heavenly and Earthly Divine Hearts.

"The Heavenly and Earthly Divine Hearts can only enhance the spiritual energy to the peak of level twelve, but this gray crystal—if I'm not mistaken—could enhance the mental strength of a second-level Super Warrior... If I had known, I would have used those Divine Hearts first and then this gray crystal.

Now, using those Divine Hearts will be much less effective, and it will be very difficult for me to break through to the Super Warrior realm..."

Half a day later, after stabilizing his mental strength level, Lin Yun opened his eyes and said with a slight sense of lament.

He couldn't help feeling a bit of regret. The usual routine was to use lower-grade treasures first and then higher-grade ones... now, it was a pity.

"However, if I had used the Heavenly and Earthly Divine Hearts, I don't know how long it would take to refine them, and I probably couldn't refine them inside this Heavenly Principle Tower, which wouldn't have allowed me to increase my strength in time..." Lin Yun paused in thought.

Upon this reflection, the sense of regret in Lin Yun's heart diminished significantly.

As he was challenging the Heavenly Principle Tower, naturally, the stronger he was, the better—especially now, as he was very likely to encounter many Ghost Practitioners who were skilled in mental strength attacks. Obviously, the higher his mental strength level, the better.

As for those Heavenly and Earthly Divine Hearts... if they weren't suitable to use, then so be it. Once he went out, he would let Mengmeng, Qingqing, and others use them, which would also be good. After all, whether their mental strength levels were low or their overall strength was weak, using the gray crystal might be beyond their endurance.

Those Divine Hearts, which had a gentle quality and slow refining speed, suited them well.