Mortal: I became invincible after becoming sworn brothers with Han Li.

Li Yunfan took out a strange, grayish-white stone that emitted a faint spiritual light and placed it on the long table.

Upon seeing this, Old Zhou's eyes flashed with a hint of doubt, and he immediately leaned closer to examine it.

Li Yunfan wasn't in a hurry; he simply stood quietly and watched Old Zhou investigate.

After a short while, Old Zhou suddenly looked surprised and suspicious. He put down the stone, turned around and went back into the inner room. When he came out, he had an old book in his hand.

Upon seeing this, a hint of surprise flashed in Li Yunfan's eyes. He hadn't expected that Old Zhou would actually recognize that strange stone.

Old Zhou quickly flipped through the books in his hands, comparing them with the stone on the table as he read.

Finally, Old Zhou paused, a look of excitement appearing on his face, and a strange light gleaming in his eyes.

"It really is it...it really is it!" he said, carefully picking up the stone and examining it repeatedly.

It wasn't until Li Yunfan tapped the table that he realized what was happening and put the stone down apologetically.

"I'm sorry, senior. I'm just too happy and couldn't control my emotions..."

"It seems you've already recognized it. Could you explain it to me?" Li Yunfan said calmly to Old Zhou.

Old Zhou then realized that the other party didn't seem to recognize the item, but he had no intention of hiding it from them. After all, although the item was rare, it was of no use to ordinary cultivators.

"Of course! This treasure of yours is actually called 'Spiritual Material,' a special material that only ancient cultivators could refine, and it's generally used to forge various powerful magical artifacts!"

Li Yunfan was slightly taken aback. This strange stone actually had such a great background?

Then he thought of the dark red skeleton in the cave in the Taiyue Mountains, and a bold idea came to his mind.

"Could that skeleton belong to an ancient cultivator? Otherwise, how could these spiritual materials have appeared near the altar...?"

"Does Senior have any remaining spiritual materials? This junior..."

Before Old Zhou could finish speaking, Li Yunfan shook his head and said, "I only have this one piece."

Upon hearing this, Old Zhou's face showed disappointment, and he then began to inquire about the origin of this spiritual material.

"Don't you think you have too many problems?" Li Yunfan narrowed his eyes slightly and said with a hint of coldness on his face.

"Senior, please calm down. I was just too anxious! It's just that this spiritual material is of great use to me, so..." Old Zhou's expression changed, and he hurriedly explained.

Li Yunfan stared at Old Zhou for a while before letting out a soft hum and regaining his composure.

"This spiritual material of yours, senior, is enough to exchange for any set of formations here!" Upon seeing this, Elder Zhou felt relieved and let out a soft breath.

"If this spiritual material is truly as you say, refined by ancient cultivators, its value is probably not something that your set of formations can offset..." Li Yunfan said meaningfully.

Old Zhou sighed inwardly, then explained, "This piece of spiritual material in your hand, senior, would be worthless outside, but to me, it is of considerable value. If you don't believe me, senior, you are welcome to take the material and ask around!"

After a pause, he continued, "Actually, even if this spiritual material were in your hands, it wouldn't be of much use. After being refined by ancient cultivators, it's impossible to use modern refining techniques to turn it into a magic weapon. It's practically a piece of waste stone."

Li Yunfan was taken aback. Was there really such a thing?

However, he did not completely believe Old Zhou's words. Instead, he narrowed his eyes slightly, stared at Old Zhou, and remained silent.

Seeing this, Old Zhou turned to the last page of the book in his hand and pushed it in front of Li Yunfan.

"When the senior looks at the records in the classics, he will naturally know that what the junior says is true!"

Li Yunfan looked down, and a strange expression gradually appeared on his face.

The reason is that it contains a secret technique for refining arrays, and the key ingredient is spiritual materials!

"Senior, I don't have much talent in cultivation, but fortunately I have some knowledge of formations. Now that my lifespan is almost over, my greatest wish in this life is to be able to refine a world-shaking formation before I die. I hope you will grant my wish!" Old Zhou solemnly said to Li Yunfan.

"This spiritual material is indeed of little use to me, so it's fine to give it to you, but..." Li Yunfan hesitated for a moment before slowly saying.

"Please enlighten me, senior!" Old Zhou said, his expression somewhat excited.

"I can exchange the spiritual materials for you, but I'm also somewhat interested in the Dao of Formations. I wonder if you could part with this book?"

Upon hearing this, Old Zhou was taken aback at first, then frowned, a look of difficulty on his face, and after thinking for a while, he finally spoke.

"I'm afraid I'll have to disappoint you, senior. This book is a family heirloom and I absolutely cannot hand it over to you. However, I'm willing to offer you my own insights into formations!"

"Okay, but I hope you can make a copy of this book. That should be fine, right?" Li Yunfan nodded and said.

Old Zhou relaxed, a smile appeared on his face, and he nodded in agreement.

"I can agree, but please don't tell anyone!"

"Can!"

The two then formally began the transaction. Old Zhou handed over the classic text to Li Yunfan for replication, and at the same time took out a jade slip from the inner room and gave it to the other party.

Li Yunfan also handed over the spiritual materials to Elder Zhou, and at the same time took away the "Soul-Locking Bewildering Array".

After an incense stick's time, Li Yunfan finished the replication and left Old Zhou's shop. He took out three low-grade spirit stones and threw them to Feng Yu before flying away on his magical artifact.

Right after Li Yunfan and Feng Yu left, Old Zhou closed the shop door and took the spiritual material back to the inner room.

"I never expected to find spiritual materials here! What a pleasant surprise! It seems my treasure will be successfully forged soon..."

After thinking it over, Old Zhou looked at the spiritual materials in his hand, and a strange smile suddenly appeared on his face...

However, Li Yunfan was unaware of this. At this moment, he was playing with a light red jade slip and flying towards the Taiyue Mountains with a smile on his face.

"As expected, this contains the array formation from that altar. My painstaking effort in replicating it was worthwhile..."

About two days later, Li Yuanfan returned to the large cave deep in the Taiyue Mountains.

With a wave of his hand, Li Yunfan released a futon and sat down cross-legged, taking out the jade slip to begin studying it carefully.

"Judging from the patterns on the altar's array, it shouldn't be a dangerous array, but rather a maze to block divine sense and conceal spiritual energy..."

After half a day of contemplation, Li Yunfan was finally able to confirm the type of the altar formation and found a way to break it in Elder Zhou's insights on formations.

He slowly opened his eyes, got up and walked towards the altar.

Looking at the array patterns on the altar, Li Yunfan narrowed his eyes slightly, and then found a large array pattern on the side of the altar.

He raised his palm and placed it on the array pattern. His spiritual energy was intermittently injected into the array pattern at a special frequency. At the same time, his divine sense slowly invaded the array and began to use the method to break it.

"Bang!"

About half an incense stick later, the array patterns on the altar suddenly shone brightly, followed by a muffled sound, and the array was finally broken by Li Yunfan!

The instant the formation was broken, Li Yunfan's divine sense detected the entire altar and the dark red skeletons floating on it.

However, before he could even rejoice, he suddenly noticed a flash of red light in the empty eye sockets of the skeleton…