It is well known that among the twelve states, the two evil cultivators Purgatory Gate and Fierce Ghost Sect are the most high-profile, while Fierce Ghost Sect is relatively low-key.
As a result, the Purgatory Gate is often targeted by the righteous forces such as Taiyi Sect, whereas the Fierce Ghost Sect is more cunning. Because of their low-key actions, they even have some dealings with various righteous sects.
As long as the Fierce Ghost Sect doesn't do anything out of line, none of the righteous sects would take them too seriously and would simply turn a blind eye to avoid further unrest.
Although all the sects appear to be friends with the Fierce Ghost Sect, everyone knows that the Fierce Ghost Sect is an ungrateful wolf that cannot be tamed. They are always on guard against the Fierce Ghost Sect doing something outrageous.
Taiyi Sect is no exception, having planted spies within the Fierce Ghost Sect long ago.
Things turned out just as they suspected.