How did Yan Shuangying know the identity of Kenji Okahara?

Yuexin Zhang, who was eavesdropping outside the door, learned that Beowulf, whose face was festering at this time, actually had only a layer of epidermis. His real identity is Yuan Gang Shinji, a Japanese, and he immediately told Yan the news. Yan Shuangying realized that Kenji Okahara, whose official position was very low, changed his face just to take advantage of his higher position to seize the treasure of heaven.