Killing intent was different from the aura of an expert.
Instead of it being a representation of how powerful the expert was, killing intent was a representation of their intention to kill.
Unlike aura that increased with the cultivation of an expert, killing intent was only developed by killing people.
The killing intent that Lin Fan had was so intense that these men couldn't move even though they were Platinum Realm Experts. Just how many people had Lin Fan killed to develop this killing intent?
Well, Lin Fan's killing intent didn't just develop from killing people, it was more developed by killing beasts.
Lin Fan's main training was fighting against beasts in the cultivation realms that the system gave him, which allowed him to draw out potential through combat. The number of beasts that Lin Fan has killed with his pets were already too hard to count.