This Castle Knight Defense Line in Tesser Kingdom's peak period was indeed effective.
When small monster incursions happened, those Lords who watched over each other could eliminate them.
For large monster armies, those Lords who held their ground and waited for aid were like nails firmly planted, preventing them from moving freely until the Royal Family's army arrived.
When the Royal Family fell into decline, and monsters attacked in large numbers, those local Lords couldn't wait for reinforcements and were gradually devoured, as Nort Castle lasted relatively long, not due to strength, but because of its good geographical advantage, being close to inland and protected by twin rivers, eventually forcing a complete evacuation.
Now Gaven directly solved it from the root, with the high mountain races guarding, those monster races could not peacefully thrive in the Marching Mountains.
Unable to form a scale, naturally, they cannot cause harm.
