Among the hundred arts of immortal cultivation, with their long and ancient origins, the art of formations had always been extremely useful.
A powerful formation, so long as it was filled with enough Spirit Stones, could be controlled by a few minor cultivators; even if they faced a high-level immortal cultivator, there would be nothing strange about fighting and defeating them.
Formations were usually divided into two kinds.
One kind was extremely complex and could not be moved. Generally, the major sects and clans used them to protect their headquarters.
The other kind used ingenious mechanisms to create simple, easily portable Formation Disks and Formation Flags, which could be taken out to fend off enemies when encountered.
Setting the first kind aside for the moment, what the Four Friends of Yan Mountain were using right now was clearly the second kind.
And a good set of Formation Flags was not something ordinary immortal cultivators could afford. Its value even far surpassed that of a top-grade Ancient Treasure.
Although the Four Friends of Yan Mountain were poor, that only meant they did not have many ready Spirit Stones left; the treasures on them were actually quite good. Lin Xuan's learning was broad, and he had also studied the art of formations. At this moment, he did not hurry out, but concealed himself to the side, planning to observe the situation first.
To be fair, that formation truly was quite good. However, the gap in cultivation realm between the four of them and their opponent was simply too great. As time passed, they gradually became unable to hold on. There was no suspense at all about the Heaven Heart Toad breaking out of the formation; it was merely a question of time.
"Croak!"
Its cry was also like a toad's, but much