Talent [1]
The Beast Domain wasn't quite as developed as its peers.
It wasn't a matter of strength or anything of the sort. It was an unequivocal fact that the Beast Domain possessed more than enough strength to be revered, which was why they hadn't been targeted until now.
However, Beasts didn't have a forgiving culture.
The law of the jungle that became a metaphor for the atmosphere of society came directly from their inherent culture, and this law didn't change at a universal scale.
If one lost, one would die. If one spared their enemy, one would be regarded as weak and they'd likely fall to revenge in the future.
When such a law prevailed, it was difficult to keep a large number of powerful people around at the same time.
The difference between the Beast Domain and the other Sectors was this.
Rather than a large quantity, they had limited quantity with extreme quality.