Many people saw Yi Yun studying the laws in the passageway but thought nothing of him. They passed right by him and continued walking towards the Divine Perish Hall's interior.
In fact, they had also sensed the laws in the passageway but never thought to study them closer. The ancient battlefield had many places with such strange laws. Many predecessors had put in great effort to study these laws, but to no avail. Therefore, they didn't bother wasting their efforts.
Most warriors entered the ancient battlefield with jade slips filled with the experiences of their predecessors. They knew which forbidden lands were of the greatest value and which places had the most opportunities. There were even some unique obstacles that the jade slips had information on, allowing the holders to pass through them by pulling a trick.
