Nowadays on Earth, the number of monsters far exceeds that of humans. Every once in a while, there would be a monster attack on cities. Although humans have managed to hold their ground, they are always in a passive defensive state.
Monster attacks on cities are not disorganized; they are commanded by a high-level monster.
The lowest rank of this commander is A-level; B-level monsters cannot command other monsters to attack a city.
On land, A-level monsters have already become very rare. Those Advanced War General teams and War God-level teams, if they know of the appearance of an A-level Mutant Beast, will definitely go to kill it immediately. Not only can they earn a lot of profits, they can also prevent monster attacks on cities.
So it is normal for A-level monsters to rarely appear around Base City, and it is normal for Shi Lei and his team not to know about this situation.
Or maybe they know, but just didn't think about it.