Ling Han had done it deliberately.
The five ancient great sects were so despicable, so Ling Han would naturally be happy to give them some trouble. Moreover, the more people enrolled into the Restore Heaven Academy, the more parties would Ling Han be able to persuade into joining his camp.
His goal was to establish a great empire and unite the whole realm. Thus, he would naturally not mind it if some parties were stronger, or some parties were weaker.
Who cares, I'm merely here to conquer.
Yet Ling Han did not dare go too far, either. Otherwise, he would become a target of the Restore Heaven Academy. Now, he could only act secretly, and once he had done what he wanted, he'd just run, and no one would know that it was him.