And it is because of this the western border tribes could never have expanded inwards.
They are trapped.
It is the same reason why Valgrun with all of his talents knows he could not expand outward.
When Bolghar was there, the Khagai tribe under Valgrun could not expand, but even now when he became one of the largest tribe in the western border, even then he could not act.
The method to suppress the western border tribe is not some secret.
One might think isn't informing the enemies on the western side would make you be condemned by all the tribes in the Steppe?
After all, isn't the western border tribe are the tribes that protected the western borders? Surprisingly enough, the only one that would condemn such act would be the tribes on the western border. Any other chief on any other side of the Steppe would at most just send some strongly worded letter and would do no action.
Interest….are paramount.
