For an enclosed space, using echolocation to determine its area was undoubtedly the simplest and quickest method.
Reilo extended his right index finger.
Bang!
The Bubble Technique burst, and sound waves of a distinctive frequency spread out.
One second.
Two seconds.
Three seconds.
Four seconds...
A long while later, when the faint echo—almost imperceptible to an ordinary person's ears—finally returned, the materialized Mental Power spread across the surface of Reilo's skin keenly detected the slight tremor in the air.
"This is actually a massive underground cavern more than fifty kilometers across. It might be even wider!"
This was clearly far beyond Reilo's expectations.
"These Witchers are pretty good at hiding."
Reilo murmured.
Just then, a figure flashed through the cascading yellow sand behind him. Bibilis caught up, looking with evident surprise at the vast underground lake.
Crack, crack, crack.
Before Bibilis could say anything, cracking sounds came again from the fractured crust above them, where the yellow sand poured down. The next moment, with a BOOM, several times as much sand as before suddenly cascaded down. In an instant, it filled the deep pool beneath their feet, and the sand slurry quickly spread in every direction.
"The fractured plates can barely support the weight above them anymore. It won't be long before this place is completely buried," Bibilis said after looking up to assess the plates.
"Who dares trespass into the forbidden grounds of the Warlock Palace?!"
An enraged roar reached them before its owner did.
Amid the rumbling explosions of fire, several points of light flickered in the distant reaches of the dim underground space, flying toward them at great speed.
Reilo and Bibilis glanced over. A red-robed Witcher, surrounded by three skeletons engulfed in blazing flames, was rushing toward them. When he saw the yellow sand pouring down