Ye Chen coughed and touched his nose tip, "Xiong'er and I joined the auction of the Ghost Black Market a few days ago. I just heard of it."

Xu Fu turned aside, "The core is the top one I've known. It's five-pattern."

"Is it hard to refine?" Ye Chen looked at Xu Fu in doubt, "Even Danchen cannot refine it?"

"Are you kidding me?" Xu Fu glimpsed at Ye Chen angrily, "Each core has its recipe. Without the recipe, even Danchen doesn't know how to refine the core. Even if he has the recipe, he probably can't find all the materials."

"Sect elder, do you know who got the empty darkness…?"

"You're so verbose." Xu Fu kicked Ye Chen towards the stove, "None of your business."

He flung an ancient volume to Ye Chen and cursed, "This is the recipe of the refuel core. Read it carefully. Refine the core after mastering the method. Don't be lazy."

"All right!"

Ye Chen opened the recipe tenderly.

Its content startled him.

The refinement of cores with a strict requirement of fire was more intricate than that of the jade spirit liquid. A mistake of a tiny link would result in failure.

"The recipe of one-pattern spirit core is so complicated!" Ye Chen flicked his tongue.

The difficulty would not block his way to be an alchemist. He recalled Xu Fu's refinement while comprehending the recipe and captured a hint of the refinement.

Xu Fu snoozed on chair and sometimes opened his eyes to check Ye Chen's status.

When night fell, Ye Chen put the recipe aside.

He took a nap, the scene that Xu Fu refined the refuel core rebroadcasting in his brain.

After a while, he opened eyes slowly, and took a deep breath. As he summoned his thought, the true fire burned in the stove, where some spirit herbs were plunged.

He had a good command of the flame with the experience of refining the jade spirit liquid.

The essence of the herbs was extracted and more spirit herbs were flung into the stove.

He belittled the intricacy of core refinement and could not control the fire well at his first time.

He failed.

Ye Chen stopped and sought his mistake. As the fire danced in the stove, his second round of refinement started.

Setbacks occurred to him incessantly.

The ashes of burned spiritual herbs scattered over the ground.

Xu Fu prepared hundreds of spirit herbs for the refuel core, so that Ye Chen could summarize his experience in the process and understood the truth of core refinement.

Until dawn, Ye Chen did not succeed yet. The refinement over a night consumed much of his soul energy, and he looked pallid with a boozing head.

Gasping, he swayed and nearly kneeled down on the ground.

"Success won't come to you if you rush for it." Xu Fu replied.

"I look down upon core refinement." Ye Chen shook head helplessly.

"Core refinement needs alchemists to be serene, just like cultivation practice." Xu Fu glanced at Ye Chen and reproached, "You haven't found inner peace."

"I…I see." Ye Chen accepted Xu Fu's instruct.

Ye Chen did not calm down. He used to yearn for being a powerful cultivator and the intense atmosphere of battles, but not adapt to the tranquility when refining cores.

"Take it and continue." Xu Fu threw a core to Ye Chen, "If you cannot even refine the refuel core. I really doubt about your ability to be an alchemist."

Ye Chen took the core and put it in his mouth.