The Hidden Formation was an Inscription Formation that could hide other Inscription Formations. Only Inscription Masters with Spiritual Energy at the Martial Monarch Stage could inscribe and set up such a formation.
If Duan Ling Tian was not an Inscription Master, he would not be able to notice the Illusory Formation that was merged with the Hidden Formation.
Moreover, he was not just an average Inscription Master, he was an outstanding one.
Therefore, he realized what was happening with the help of his Spiritual Energy after Lu Zhi and the lecherous middle-aged man entered the Illusory Formation and encountered the Hidden Formation.
That was the reason why he managed to stop in time and did not enter the Illusory Formation.
"You're an Inscription Master?" The old man's eyes narrowed. He had a shocked expression on his face when heard Duan Ling Tian's words.
Previously, he had made an effort to research the purple-clad young man standing before him.