"What is this thing, why is it so hard?" Li Xiu frowned as he looked at the grayish-white substance.
"That is Demon Ash, made by grinding materials from Demon Spirits into powder, then mixing it with iron, zinc, chromium, sand ash, and other materials to create a cement-like substance. The Demon Ash here is made using materials from an S-Class Demon Spirit. Your little E-Class Demon Spirit, even if it hacked for a year, wouldn't be able to break the door open," a hoarse voice sounded behind Li Xiu.
Li Xiu was slightly startled, turned around, and saw the wild-looking Ximen Guan sitting there coldly watching him.
"You haven't gone mad?" Li Xiu looked at Ximen Guan and asked.
"Anyone trapped in a place like this for decades would go mad. I'm insane, but I'm not stupid," Ximen Guan said coldly.
"Are you really Ximen Guan?" Li Xiu asked again.
