After decades of quarreling, they finally succumbed to the immense external pressure brought about by the alliance of Taiping Dao and the Jiuzhou Immortal Sect.
Especially about fifty or sixty years ago, the Evergreen Immortal Sect, deviating from its defensive stance of thousands of years, began to actively invade the Western Domain, showing an intention to reignite a great war and take the opportunity to eliminate the Jiuzhou Immortal Sect.
Facing a crisis of survival, inside the Jiuzhou Immortal Sect, they eventually reached a consensus.
That was to reconcile with Taiping Dao and improve their relationship, striving to convince them to join forces against the Evergreen Immortal Sect.
There was no choice, the pressure the Evergreen Immortal Sect placed on the Jiuzhou Immortal Sect was too great.