It wasn't that Wu Wei was targeting Sixth Brother, nor was it that he was being cruel. It was just that if he did this, Wu Wei wouldn't be able to collect the fragments of the [Eight Spearman Strikes], nor would he be able to collect the energy of the [Dragon Flag]'s effect 4.
Under Wu Wei's control, Sixth Brother did not kill anyone.
When monsters attacked, it was responsible for freezing them. Fourth Brother was responsible for sending the frozen monsters to Wu Wei and letting him collect the fragments. After that, he would let the Dragon Elephant Dao Soldiers harvest them.
The operation of this assembly line was quite impressive.
They had no ability to resist at all in front of those who were below the second stage of the Rudiment of Dao. They could resist for a moment at the third stage of the Rudiment of Dao, but it was only for a moment.