Despite this, Liu Chen was not satisfied with the status quo. He took a deep breath and resolutely took out a Gu worm from his embrace. This Gu worm looked like a stale steamed bun, emitting a nauseating odor. This Gu worm was precisely the Starvation Gu. Like the Five Labors Gu, it had the effect of enhancing the soul's foundation, but its side effects were equally severe.
Liu Chen activated the Starvation Gu without hesitation, and then activated the Gu worm's power. As the Gu worm took effect in his body, his soul was once again strengthened. However, this strengthening seemed somewhat superficial, like an overinflated balloon that could burst at any moment.
At the same time, the side effects of the Starvation Gu also began to manifest. A strong sense of hunger came from Liu Chen's abdomen, as if countless ants were gnawing at his internal organs. He constantly swallowed saliva, but due to the effect of the Coptis Gu, his mouth was filled with a bitter taste.
This painful torment made Liu Chen almost unbearable, but he still gritted his teeth and persisted in strengthening his soul.
Finally, when he felt that his soul had been strengthened to its limit, he stopped the soul-strengthening process and took out a Sword Soul Gu, preparing to use it to refine his soul.
The Sword Soul Gu was small and exquisite, only about the size of a thumb, and glowed with a dark blue hue, like a delicate treasured sword. When Liu Chen continuously injected his true essence into it, this Sword Soul Gu seemed to be endowed with life, and began to undergo wondrous changes.
Under the nourishment of the true essence, the Sword Soul Gu gradually expanded, eventually transforming into a dark blue Soul Sword several feet long. This Soul Sword emitted a cold, eerie light, and wisps of soul mist lingered around its blade, making it appear mysterious and strange.
Under Liu Chen's control, this Soul Sword, like a nimble fish, swiftly swam into his mind. As soon as it entered his mind, the Soul Sword exploded with astonishing power, like a lit powder keg. The incomparably sharp Sword Soul mercilessly slashed at Liu Chen's own soul, with a speed like lightning streaking across the night sky.
However, Liu Chen's soul was not so easily defeated. After being strengthened threefold by the Coptis Gu, Five Labors Gu, and Starvation Gu, his soul's foundation had surged to an astonishing degree, like a small giant.
Facing such a fierce Soul Sword attack, Liu Chen's soul not only did not retreat in the slightest, but instead, without showing any weakness, raised its fists and fiercely smashed towards the Soul Sword.
In an instant, the two collided fiercely, and in this intense collision, wisps of soul mist scattered from both of them. These soul mists seemed to possess a special attractive force, gathering towards Liu Chen's soul.
Liu Chen's soul opened its mouth wide and swallowed all these soul mists. As the soul mist was continuously absorbed, Liu Chen's soul also gradually shrank, but at the same time, it became increasingly solid, like a piece of steel tempered a thousand times. And in the soul's hand, the rudimentary form of a Soul Sword vaguely condensed.
Once this Soul Sword was completely solidified, Liu Chen's soul would also undergo a qualitative transformation, becoming a true Sword Soul. At that time, his control over the Sword Path Gu worm would reach a higher level, becoming even more proficient.
After such high-intensity soul tempering, Liu Chen's spirit finally succumbed to the burden, slowly withdrawing from his cultivation state as if all his strength had been drained.
This long and arduous cultivation process had lasted for more than half a year for Liu Chen.
During this period, he continuously used the Sword Soul Gu to temper his soul, enduring such torment every half a month, each time lasting for three days and two nights.
However, all these efforts were not in vain. Now, Liu Chen's soul foundation had reached an astonishing level of three hundred human souls!
This achievement was not only due to his own tenacity and perseverance, but also to the miraculous accelerating effect of the Three Watches Gu. If it were any other ordinary Gu Master, it would probably take several years to reach such a level.
The Living Treasure Window indicated that it could block the Gu Immortal's detection. As long as the Living Treasure Window did not intentionally emit its aura, it would be no different from an ordinary window, completely unnoticed by others.
Because of this, Liu Chen did not put the Living Treasure Window into the System backpack as usual this time, but let it stay in place. This made the Living Treasure Window even happier, as if just being able to see Liu Chen could make it happy.
Time flew by, and in a blink of an eye, more than half a year had passed. During this time, the effect of the Five Labors Gu on Liu Chen had become increasingly weak, unable to keep up with his increasingly advanced soul cultivation progress. After careful consideration, Liu Chen resolutely decided to completely eliminate the drawbacks caused by the Five Labors Gu remaining in his body, to prevent this situation from continuously affecting his cultivation state.
Liu Chen took a deep breath and softly uttered, "Dark Cloud Gu."
As he activated it, dark, inky clouds, like rolling thick smoke, emerged. These dark clouds seemed to have a life of their own, rapidly descending and gathering beneath Liu Chen, like a giant dark cloud cushion, steadily holding him up.
Immediately after, Liu Chen unhesitatingly activated another Gu: "Light Cloud Gu."
In an instant, pure white Light Clouds rose into the sky, reflecting the dark clouds below. The Yin and Yang clouds Gu responded to each other, intermingling, with faint streaks of lightning flickering between them.
These lightning bolts, like silver snakes dancing wildly, occasionally struck Liu Chen's body. However, this was not ordinary lightning, but rather the power of thunder and lightning released under Liu Chen's precise control, specifically targeting the Dao marks left by the Five Labors Gu on his body.
Each bolt of lightning accurately hit its target, and powerful energy raged within Liu Chen's body, gradually eroding the Dao marks left by the Five Labors Gu. At the same time, wisps of black Qi would rise from the destroyed Dao marks. These black Qi were the residual power of the Five Labors Gu.
During this process, Liu Chen himself was inevitably subjected to the electric shock of the lightning. His body trembled uncontrollably, as if being impacted by an invisible immense force. However, Liu Chen did not flinch because of this.
His body had been transformed by the Sword Bone Gu, becoming exceptionally tough, and coupled with the Sword Heart in his chest, he was able to endure this ordeal head-on.