Chapter 3318

This could only prove that the difficulty of setting up the Mysterious Rank Heart Formation was far beyond that of a normal high-level array.

"He deserves to be the number one in the Ethereal Land!"

"The Celestial Martial Emperor's Heart Array Technique isn't something that can be learned so easily!"

Zephyr Khan secretly sighed, rubbed his temple slightly, and once again devoted his mind to the Mysterious Rank Heart Formation.

Failure!

Failure!

It still failed!

...

After countless failures, even Zephyr Khan had forgotten the existence of time.

Every time his spirit energy was exhausted, he could only close his eyes again and slowly recover his spirit energy.

In the end, even Immortal Heart began to release wisps of energy to help Zephyr Khan recover his soul.

It was because!

It took too much spirit energy to carve the heart formation of the Mystery Class, especially the mind.

Heartforce was an aspect of spirit energy, but at the same time, it was quite unique, because it w