"Waiting around for internal strife to break out between the human and Monster races is simply not viable. The Second Grand Sage Lord is right: both sides have people with long-term vision, and they will not resort to infighting at a juncture like this.
However, we can certainly meddle elsewhere—through beast tides, for instance.
This is the most effective method the Monster race uses to control its population, and I expect they will proceed with it as usual."
Chapter 758