Sneaked in

Taisu Sect was indeed hidden in the void. By setting up the formation, space was extended from this side of the world.

Even if outsiders knew that Taisu Sect was in the north, but without depending on the mountain or understanding the profound, within the void, even if it was right in front, one could not enter.

The aurora was the ultimate formation that Taisu Sect made use of in combination with the spiritual opportunity of heaven and earth to protect the sect.

For outsiders who did not know, they would simply assume that it was a natural phenomenon of the world. Even if they observed it closely, they would not be able to relate or to even realize that there was spiritual opportunity circulating in it.

Even if one could spot some oddities, the formation left no trace or trail for anyone to sneak into.