Roan could have asked Kassie to play the strict commander role to help Calina. All Kassie had to do was to say a few words. For example, she would follow their entire new Unit with her Spiritual Sense. If she saw as much as a single cultivator showing signs of rejecting Calina's orders, she would kill that guy or girl straight away.
With just this much effort, everyone in Calina's new Unit would be forced to follow her orders to the letter. After all, none of them wanted to die from an attack of a Nascent Soul Realm cultivator from behind. The other sects gave Kassie full control, so they knew she could do it.
