Li Ming knew what a secret realm was. That was why he had made up his mind to go into seclusion!
There were countless opportunities in the mystic realm. If he was lucky, he would be able to get one or two good materials. That would be a huge gain.
However, if you treated this mystic realm as your spiritual field and could pick as you pleased, then you were gravely mistaken. But now, Tian Songzi actually wanted them to explore. Clearly, this secret realm was an undiscovered place.
If it had already been explored by others, then the treasures inside must have been taken away by others. There was no need to let others in.
In the mystic realm, opportunities and dangers coexisted. There were many demonic beasts, and any treasure would be guarded by a powerful demonic beast.