According to what Xuan Lu said before, there is a thunder pond here.

And the power of thunder and lightning formed around the thunder pool was transformed into extremely pure spiritual power due to a certain relationship.

Anyway, it is purer than the peripheral spiritual power.

He practiced there back then.

This is also the reason why Xuanlu specially marked it on this map.

After thinking for a while, Lin Yu put away the map, looked for the direction, and then looked over there.

As night fell, Lin Yu finally arrived at the place marked by Xuan Lu.

But looking at the overgrown shrubs around him, Lin Yu was dumbfounded.

There is no underground cave mentioned by Xuanlu.

Lin Yu took out the map again and compared it. Lin Yu was sure that he was not looking for the wrong place, it was here.

Because Lin Yu felt a little spiritual power containing the power of thunder and lightning around here.

Putting away the map, Lin Yu turned on the perspective and looked at it.

After a while, Lin Yu really found a cave in this place.

It's just that the hole was covered by shrubs, and there was a formation covering it.

This made Lin Yu a little confused.

This formation is absolutely man-made.

Could it have been given by Senior Xuanlu?

If not, then there are only outsiders.

In other words, there are others in this secret realm, not just Lin Yu.

But after thinking about it, Lin Yu felt that it was impossible!

It should have been donated by Senior Xuanlu.

Maybe he just forgot to tell himself.

Lin Yu finally came to this conclusion.

But the conclusion was the conclusion, and Lin Yu was on guard.

It’s impossible not to be careful in a place like this!

If the thing turns into some ferocious beast, it will be troublesome.

After quietly destroying the formation, Lin Yu himself placed another warning formation on it.

After doing all this, Lin Yu took out Prince Ning's Sword, cut off the bushes outside the cave with one sword, and then walked into the cave.

Walking along the underground cave, going deeper and deeper, and every time he went down, Lin Yu felt the power of thunder and lightning more deeply.

At this time, Ziyuan in Kunpeng's bag also spoke.

"Lin Yu, have you discovered something good?"

Because she also felt the power of thunder and lightning inside Kunpeng's bag.

The Amethyst Lion was extremely sensitive to the power of thunder and lightning, so she felt it when Lin Yu arrived outside the cave.

But she didn't speak.

If Lin Yu had wanted to leave before, then she would have spoken.

Otherwise, you will owe Lin Yu another favor.

But if Lin Yu came here himself, it would be different.

Hearing this, Lin Yu naturally didn't know the little thief Ziyuan's thoughts, but he nodded honestly and said: "Yes!"

After saying that, as soon as his thoughts moved, Ziyuan appeared next to him.

Ziyuan, who had just been taken out of Kunpeng's bag by Lin Yu, was still looking at Lin Yu with an unhappy expression.

It was as if she was talking about why Lin Yuhu took her out without her permission, and it was not like she couldn't come out herself.

Seeing this, Lin Yu had become accustomed to recognizing his father-like existence and ignored his unhappy expression.

"Do you know what's in this?"

Because Lin Yu was already a little flustered at this time.

But it hasn't reached the bottom yet.

It was completely different from what Xuanlu described at that time.

Much more powerful than that.

Hearing this, Ziyuan said: "Do you know how many types of thunder and lightning there are?"

!

Hearing this, Lin Yu was stunned for a moment, and then quickly looked it up.

After a while, Lin Yu said: "There are three types of thunder and lightning!"

"Human mines, land mines, and sky mines!"

"Among them, human thunder is like the pill thunder caused by alchemy, or the thunder and lightning caused by breakthrough. It was the thunder and lightning when you broke through to the middle stage of the Earthly Saint Realm!"

"Or the heavenly vow I made at that time. If I break my promise then, it will be a thunderbolt because I have a goal!"

Ziyuan nodded and then motioned for Lin Yu to continue.

"Then there are landmines, which are usually the power of thunder and lightning caused by the center of the earth for some reason, such as Xuanyin landmines, earth vein fire mines..."

Ziyuan nodded again.

"The last one is thunder!"

"This kind of sky thunder does not mean it is caused by anything. The thunder and lightning caused by the sky can be called sky thunder!"

"The necessary condition for sky thunder is that there is no target to form thunder and lightning in the sky!"

According to the records in the inheritance, the Emperor Immortal of Qingxu entered a secret realm, where the sky was filled with dark clouds and thunder rolled.

That kind of thunder and lightning not only contains the violent power of thunder and lightning, but also contains the source of spiritual power.

It’s harmful to the human body, but it’s also beneficial!

At the same time, it will also form when there is no goal!

This is the difference between human thunder and heavenly thunder.

When the Qingxu Emperor entered that secret realm, he finally called it the Heavenly Thunder Secret Realm.

The sky was full of thunder as far as the eye could see. The secret realm at that time also helped him break through to the perfection of the Earthly Saint Realm.

After the introduction, Ziyuan nodded with satisfaction.

"I didn't expect you to know something, I thought you didn't know anything!"

"Rubber!"

Seeing Ziyuan mocking him again, Lin Yu had no choice but to pretend not to hear Ziyuan's words.

"Is that a human mine or a land mine?"

Lin Yu asked immediately.

Because except for sky mines, which cannot exist underground, there are also human mines that can exist underground for some special reasons.

"There is Xuanyin Thunder Vein inside!"

"It's more powerful than the Xuanyin mine you mentioned earlier!"

Hearing this, Lin Yu was stunned.

A ball of thunder is not enough, how about a whole thunder vein?

What the hell!

"Then there might be thunder spirits down there!"

Just listen to Ziyuan continue.

These words directly frightened Lin Yu who was already stunned on the spot.

Thunder spirit?

That’s a thing made from elements, you’re just kidding!

It was only mentioned casually in the inheritance.

Even the Qingxu Emperor had seen the ice spirit back then, but at that time the Qingxu Emperor did not take it in because it was not easy to become a spirit.

There are no records after that.

What else does this need to explain? This is enough to show how valuable this thing is.
To be continued...