The Scum Is Tempted 

They really didn't know this. After all, to them, an enemy is an enemy, unless there is something with the enemy that affects all of them. For example, Wu Ran who they fought against five years ago. He was actually disguising himself as Ming Ye and Luo Shi was truly hurt not only because his best friend betrayed him and turned to become their enemies, but that his best friend also humiliated him… tarnished his honor as an elder of the Youxiwang Sect. 

Recalling the two great elders of the Youxiwang Sect, Dong Zheng can't help but sigh. "They don't know the switch up of their previous sect leader and Ho Yue's elder brother?" he asked. 

They thought all this while that the enemies knew who their sect leader was, as he was the leader of their group after all. So how could they not know who their sect leader is? How can they not know that their sect leader actually changed to another person?