After confirming the thickness of the stone wall, Shard did not continue to expend his spirit using "Feliana's Witch Light" to melt the stone wall. Instead, he removed the cloth strip wrapped around the sword scabbard and inserted "Night Watchman" into the hole melted by his arm.
Taking a deep breath, he drew the elements and spirit onto the blade of the "Night Watchman":
"Light of the Witch!"
In an instant, golden light radiated from the blade, and the expanding light melted a large hole in the stone wall. Shard was pleased as he withdrew the "Night Watchman," then bent down and crawled through the unusually smooth opening into the space behind the stone wall.
The space behind the stone wall appeared to be forcibly excavated by some external force. The interior was not a regular shape, suggesting that the initial users only regarded it as a temporary base.