"I promise you! I will never step foot into the ancient city in this lifetime!" the Ghost King vowed solemnly.
Having said that, the Ghost King immediately showed a pained expression on his face, feeling the four waves of Nether King's Power seeping into the flesh of his entire body. The oath he had just made in front of the strawman began to take effect instantly; if he ever broke this oath, those four waves of the Nether King's Power would turn him to ashes in a moment.
And these four waves of Nether King's Power were the very same he had obtained after defeating the incarnations of the four Demon-Sealing Scrolls he had previously entered, along with the four fragments of the map that led to the ancient city.
"Foster father, I've already made my oath, now you must tell me about my father!" the Ghost King's voice also contained a trace of pain.
"This matter dates back to when King Nanlin and I were forced to seek refuge in the Polar Ice Land..."
Over sixty thousand years ago.