After the Thunder Serpent Immortal King's order was issued, the affiliated forces newly acquired by the Mysterious Moon Palace soon conflicted with the Thunder Serpent Sect.
In fact, Ling Yin Immortal King, to avoid conflict with some nearby sects of slightly stronger powers, immediately instructed the Mysterious Moon Palace to cease further expansion once they established themselves.
Although top forces in the Barbaric are few, it's not without Immortal Venerates and Immortal Kings. If the Mysterious Moon Palace expands too much, it can easily offend these forces, and should the Barbaric forces unite against them, the Mysterious Moon Palace would struggle to endure.
However, even though Ling Yin Immortal King halted the expansion of the Mysterious Moon Palace, its affiliated forces did not see things the same way. Upon joining the Immortal Sect, some affiliated forces that came under the Mysterious Moon Palace felt empowered and began to expand outward.