Inside the cave, there was no light at all.
Fortunately, Su Tong's cultivation had reached the Returning Void Realm, so he could still see clearly even in such a dark place.
In front of Su Tong, there was only a barrier.
This barrier, rather than something Su Tong saw, was something he felt.
"The spiritual energy from the outside is disappearing in this place!"
At this moment, Su Tong could also feel that the spiritual energy could penetrate the barrier in front of him.
Although he did not know whether the barrier was man-made or natural.
But Su Tong could feel that even with his full strength now, he would not be able to break through this barrier.
"There must be a way to open it!"
At this moment, Su Tong also understood clearly that although this barrier was powerful, as long as it was not natural, there must be a way to open it.
Of course, if it was a naturally formed barrier, then there was no need to go in at all.
Because natural means there is nothing behind it.
The reason why the major sects of the North Domain did not continue to study this was because they believed that the wonders of Yunling Island, as well as this barrier, were all naturally formed.
"If it is naturally formed, it is a bit too much of a coincidence!"
Su Tong looked at the barrier in front of him and pondered for a moment.
Then he smashed a punch at the barrier.
"Boom!"
With a loud noise, a ripple spread out from Su Tong's fist to the barrier.
But there was no reaction at all.
"As expected, this has nothing to do with strength!"
Su Tong actually understood from the beginning.
This had nothing to do with strength. Otherwise, with the combined strength of the top experts from the major sects, it should be no problem to break this barrier.
Then Su Tong looked around to see if there were any mechanisms to open it around.
Unfortunately, nothing was found.
"No mechanism, unable to break through, is it really impossible to enter?"
Su Tong's eyebrows wrinkled slightly.
After thinking for a while, he suddenly thought of something.
"If this barrier was man-made, then it must have been laid down with tremendous power, and the source of power can only be two kinds - the barrier created by oneself, or the ancient gods' language."
At this moment, Su Tong's thinking was also very clear.
Then he continued to analyze: "Given that all the exercises and spiritual techniques in the Heaven Question Continent originated from the ancient gods' language, which is the Chinese I am familiar with, then the barrier technique must also come from the ancient gods' language."
"Maybe it can be opened by using the ancient gods' language!"
Su Tong placed his hand on the barrier.
He said slowly: "By my spiritual power, open the barrier!"
At that moment, Su Tong felt that the spiritual power in his body was drained in an instant.
All of it rushed into the barrier.
A faint light appeared on the barrier, but it was extremely weak.
"There is a reaction!"
Seeing this scene, Su Tong was also overjoyed.
"Devour the spiritual energy!"
Su Tong knew clearly that the spiritual power at the Returning Void Realm was not enough to start the barrier.
So he could only forcibly devour the spiritual energy from heaven and earth to condense his spiritual power and open this barrier.
Sure enough, as the spiritual energy in Su Tong's body continued to pour in.
The barrier finally reacted again, and the faint light began to get brighter slowly.
But Su Tong was not in a hurry. Now that he knew how to open the barrier, it was just a matter of time.
After pouring for an hour, the barrier in front also reached a fairly bright level.
At this moment, Su Tong's hand also penetrated the barrier.
"Success!"
Seeing that his hand had successfully penetrated the barrier, Su Tong did not hesitate at all, and strode directly into the barrier.
Just after entering the barrier, Su Tong saw that it had brightened up in front of him.
"What is this?"
Looking at this strange place, Su Tong was also a little curious.
In this cave, it was surprisingly spacious.
In the sky, a light ball was suspended.
Su Tong felt it and found that it was completely condensed from spiritual energy.
Most of the spiritual energy that flowed in from outside the barrier flowed into that light ball.
And the light around came from that light ball.
It was like an artificial sun.
"There are buildings!"
Su Tong could see that under his feet, there were buildings, as if they were built underground.
But at this time, Su Tong did not feel any vitality at all.
That is to say, there were no living people left in these buildings.
"Go down and take a look!"
Su Tong hesitated for a moment, and jumped directly down.
After bouncing off a few times, he landed on the ground.
Looking at the ancient buildings around, Su Tong also fell into thought.
"Such buildings seem a bit like a sect."
Su Tong did not expect that under Yunling Island, there was actually a hidden sect.
"This sect should be quite old!"
Looking at the surroundings, some places revealed an ancient and antique atmosphere.
Su Tong could determine that the age of this sect was probably very long, possibly thousands or even tens of thousands of years.
"A sect that is deeply buried underground?"
Su Tong flashed a few times and came to the main gate of the ancient sect.
At this time, he saw three characters carved on the gate of the sect.
These three characters made Su Tong stunned for a moment.
Because these were not the words of the Heaven Question Continent, but three seal script characters.
"Hidden Spirit Sect!"
Looking at the familiar font, Su Tong also read it out.
But as soon as Su Tong read out these three characters, the surroundings suddenly changed.
In a trance, human shadows appeared in front of Su Tong.
"This is..."
Su Tong thought all the people of the sect had appeared.
But on closer inspection, it was different.
"This is not underground, this is... Yunling Island? The entire Hidden Spirit Sect actually covered the entire Yunling Island!"
At this time, Su Tong also discovered that everything before his eyes was just an illusion.
It was probably triggered by him reading the three characters of Hidden Spirit Sect in Chinese.
Su Tong did not expect that the Hidden Spirit Sect he had just seen underground, which he thought was just a small sect, turned out to be a huge sect covering the entire Yunling Island.
In the Hidden Spirit Sect, shadows flashed by.
Some were chatting, while most were cultivating.
Su Tong could not sense their strength, but it was not difficult to see that all these people around were disciples of the Hidden Spirit Sect, and their strength was all above the Returning Void Realm.
"Even the disciples have the strength of the Returning Void Realm? How powerful would the elders and sect master be?"
Su Tong didn't know why such a powerful sect would be hidden underground.
At this moment, everyone's expression suddenly became solemn as they looked up at the sky.
Su Tong also followed their gaze upwards.
This one look was shocking enough to stun Su Tong for a moment.
In the sky, a blood-red river rushed turbulent.
From the blood-red river, Su Tong could feel a chilling boundless aura of slaughter.
"What is that?"
At this moment, Su Tong saw that there were actually figures appearing in the blood-colored river!