I can gather experience beads

Inside the Tianji Fortress, at the core of the fortress formation.

Cao Rui stood in the middle of it, his eyes attracted by the countless magic circles that were entwined around him, and he couldn't help feeling dizzy.

He exclaimed: "It's really terrible!"

He secretly wondered in his heart what level Tianjizi's attainments in formation had reached.

At this moment, the core of the formation he saw before his eyes was a huge sphere with a diameter of about ten feet.

This sphere is the operating core of the Tianji Fortress. It floats quietly in this space, constantly emitting various signals and energy to accurately control the operation of the entire Tianji Fortress.

The magic arrays on the surface of the sphere are densely packed, entangled with each other, one ring after another, like a complicated maze.

For outsiders, if they don't get any guidance, it would be harder than climbing to heaven to figure out the operating principles of these magic arrays.

The baby Tianji appeared in front of the sphere, pointed at an area and said, "This is where the central control function of the Tianji Fortress is located."

Then, he continued to explain: "If you want to change it, you must erase this magic circle, but at the same time it cannot affect the normal operation of other parts of the Tianji Fortress."

Cao Rui nodded slightly to show that he understood, then stared closely at the extremely complex magic circle sphere in front of him and observed it carefully for a long time.

After a while, he slowly said, "Can I erase it completely and then rebuild it?"

Hearing this, Tianji Baby was stunned for a moment, then exclaimed:

"Did you see its size? And the number of arrays it covers is extremely terrifying!"

"The fortress's ability to transform, absorb the spiritual energy of heaven and earth, and randomly teleport, etc., all require complex formation attainments to create, but controlling the core is relatively simple!"

"But..." Tianji Baby changed the subject: "If someone else said that, I would definitely think he was crazy."

"But for a rune genius like you, it might be possible. It's just that the task is too difficult and will take a lot of time and energy."

"It took my father hundreds of years to refine the Tianji Fortress, and the renovation takes even longer than the new construction. So I think by the time you finish the renovation, it will probably be a long time. The demon invasion will not wait for you. By the time you finish everything, the opportunity will be gone."

After hearing this, Cao Rui nodded thoughtfully and said softly, "That's true."

"Just take it step by step."

"Baby Tianji, you will help me formulate a plan and select the magic array runes to be changed in the first step. The main task is to gain control of the Tianji Fortress."

"understood."

Baby Tianji started to use his brain and began to analyze the magic circle on the sphere.

The main thing is to distinguish which part can be erased and which part can be superimposed and engraved.

Three days later, baby Tianji felt dizzy.

"Cao Rui, it's too difficult. I don't know where to start. Many of the runes that control the center are integrated with other runes. Basically, if you move one, the whole body will move." Tianji baby said.

Cao Rui looked at the modified plan drawn in Tianji Baby's hand. With his attainments in formation, he could naturally understand Tianji Baby's thinking.

After thinking for a while, Cao Rui pointed at several rune arrays and said, "We can abandon the checkpoints in Tianji Fortress."

Cao Rui had already obtained all the things in the level, so it didn't matter if he gave them up.

The level space is freed up, and you can keep it for other purposes in the future when your attainments in magic arrays improve.

In fact, a large portion of the runes in dozens of levels have become invalid because the level rewards have been exhausted.

The only few that remain are nothing more than jade slips and spells.

After hearing this, Tianji baby's eyes lit up and he continued to analyze the sphere.

Cao Rui's decision greatly reduced the difficulty of changing the control runes of the operating core.

After all, there are more than thirty levels, and there are too many runes on the spheres that are entangled with each other. It is inevitable that you feel at a loss as to where to start.

This time, it only took half a day.

Tianji Baby finished the analysis and created a new plan.

Of course, Cao Rui has not been idle during this period. He has been studying the knowledge of magic arrays and runes given by Tianji Baby.

Cao Rui will only start the formal changes after using experience beads to upgrade them to the perfect level.

"Cao Rui, look." Tianji Baby handed the plan to Cao Rui.

"The magic array here is the control rune of the Tianji Fortress. It is formed by the fusion of three fifth-order runes. You can erase them all and then construct the control rune in the same way. Just change these few points... and you can control the entire Tianji Fortress."

With the help of the traitor Tianji Baby, Cao Rui's process of controlling Tianji Fortress was much smoother.

"I understand." Cao Rui nodded slightly.

“However, after this erasure, the core level-breaking function of the Tianji Fortress has really disappeared. This is almost the same as erasing all the magic array runes on the core.” Tianji baby sighed.

When Tianjizi built the Tianji Fortress, his main purpose was to help people pass the levels and find their successor.

Cao Rui spread his hands and said, "There's nothing we can do about it. Is the fortress's Thirteen States teleportation function still available?"

Cao Rui asked.

"I didn't move these runes with the teleportation function. If nothing unexpected happens, they should be retained." Tianji baby said.

Cao Rui nodded slightly, that was all right.

"I must understand the control runes before I can erase them."

Cao Rui took the crystal plate and began to copy the three fused fifth-order runes - control runes - on the sphere that Tianji Baby had pointed out.

Although Tianji baby knew about this control rune, he was not proficient in it.

Therefore, it is impossible to replace Cao Rui's inscription.

Cao Rui could only practice slowly with the help of the experience beads, raise it to the perfect level, and then engrave it himself.

This practice took more than half a year.

Even with experience beads, Cao Rui still has plenty of rune experience.

However, the control rune created by Tianjizi is still too difficult to control this huge space.

It took Cao Rui three full months to finally condense the experience beads that could control the runes.

After condensing the experience beads, things became a little easier.

Twenty days to get started, one month to achieve minor success, and forty days to achieve major success.

Two months complete.

For a full eight months, Cao Rui spent eleven hours out of twelve every day engraving this control rune, and finally cultivated it to the perfect level.

While Cao Rui was practicing, Tianji baby was teleported back to the Lingshou Sect and continued to refine the Lingyin jade pendant for Cao Rui, striving to give each Yunzhou cultivator a Lingyin jade pendant as soon as possible.

"The control rune has been completed. The next step is to erase the control rune on the Tianji Fortress and then engrave my own." Cao Rui's eyes flashed.

After completing the control rune, the experience and memory gained in his mind made Cao Rui understand it clearly.

He also thoroughly understood the principles of how Tianjizi fused runes to create such powerful control runes and the principles of setting control rights.

Cao Rui also had some ideas about the changes to the control runes on the Tianji Fortress. He decided to take the opportunity to add some of his own ideas and completely turn the Tianji Fortress into the core tool of his future mysterious organization in the immortal cultivation world.