Everything that Lin Yun had seen in the forest of bloody trees and the dark castle allowed Lin Yun to confirm Lesonbora's identity. He then disguised himself as an envoy for the King of the Undead.
Lesonbora wasn't suspicious at all. He was almost scared to death. He had to kneel before Lin Yun, a level-46 skeleton king, even though he was a level-48 vampire ancestor.
Normal undead creatures weren't as shrewd as Lesonbora. Lin Yun might be only in level 46, but the fact that he knew the King of the Undead's name suggested that he was very close to the King of the Undead, and might have been personally trained by him.
Lesonbora did not dare to offend such an undead creature. Even if he were the first ancestor of vampires, he wouldn't dare to defy the King of the Undead.
