With the King Slimes multiplying in number, rather than simply defending, they could even go ahead and expand the region under their control. Leaving the original ones behind, the new offshoots started to gradually roll off, making sure that not a single demonic being was able to pass, not even flying ones.
To block the flying ones, the King Slimes had to extend their "feelers," which looked more like tentacles, toward the sky, creating a complex net-like structure.
It wasn't too high, but whenever demons tried to go over it without gaining enough altitude, the feelers would extend like a spring-loaded trap, piercing through the target before dragging them down for consumption.
As they went forward, gaps appeared between the five giant slimes. The demons saw this and passed between them, but it wasn't really an opening but a trap. The feelers could also come out of their sides since the King Slimes technically have no concept of front or back!