The next day, Xiao Yu appeared in the Giant Sword Sect's Earthfire Hall.
After inspecting all the earthfire chambers, he found none of them entirely satisfactory, so he chose the largest chamber, which also had the fiercest earthfire, and remodeled it.
He dismantled the original magic formation, then dug deeper underground until he reached the subterranean lava.
Next, he built a circular stone platform a hundred feet across, enclosing the scorching, roaring earthfire within it.
Around the platform, he then laid out a vast, intricate magic formation designed to assist in refining treasures.
"Senior Great Evolution, sorry for the trouble, but I'll need you to keep an eye on the refining process. If anything seems wrong, point it out immediately!" Xiao Yu spoke into the empty air without preamble.
"Don't worry. I'm watching!" The Great Evolution Divine Monarch's voice rang out in Xiao Yu's mind.
Without further hesitation, Xiao Yu slapped his Storage Bag, and a ball of silver light abruptly shot out. It expanded rapidly, transforming in the blink of an eye into a pair of bone wings roughly ten feet across, one missing a corner and the other riddled with holes. These were none other than the Thunder Roc's bones!
He raised his hand and released streaks of golden spiritual light. With a flash of silver, the bone wings were slowly lifted above the center of the stone platform, where they hovered motionlessly.
Next, he took out more than ten high-grade spirit stones and fitted them into the auxiliary magic formation, then walked to its focal point and sat cross-legged.
After he cast several incantations, the magic formation trembled slightly and began to operate. The high-grade spirit stones lit up one after another with dazzling radiance.
Using more than ten high-grade spirit stones to refine a treasure was