The Krell came out of the deep jungle of southeastern Ve near three centuries ago, and what they did to the old kingdoms there is a thing Shyona watched from the far end of, kingdom by kingdom, for the better part of a hundred years. The Shyonans call the whole long advance the Grinding, because that is what it looked like from the north. It was less a war than a slow pressure that never stopped and never hurried, taking a realm a season at a time and leaving nothing behind to bargain with.
The refugees told it the same way every time. First the scouts, then a season where the ground itself seemed to be made ready by something patient, then the swarm. Where the swarm passed, the walls were left standing and the fields were stripped to bare soil and the people were simply gone. There was no occupier to sue for terms and no border to fortify, only a line that was a little farther north each year. Nobody who carried that account out of the south could say where the Krell had come from or what they wanted, and Shyona has never learned. It only learned that they did not stop.
Between the swarm and Shyona's own lowland stood Velkoron, the last and largest of the old southeastern kingdoms, a walled realm with a standing army and a king who held longer than any of his neighbors had. For a generation Velkoron was the buffer, and Shyona treated it as one: a useful distance, somebody else's wall. When Velkoron's envoys came north asking for soldiers, the council did what the council does. It deliberated. It weighed which houses should send how many and whether the threat was truly Shyona's to answer, and while it weighed, the grain caravans that had always come up from Velkoron came thinner, and then came as refugees, and then stopped. Velkoron fell around 3150 SD. After that the Krell jungle touched Shyona directly, along the lowland gap above Meadow Sound, and the buffer the council had been so careful never to spend its own tenants defending was simply gone.
Velkoron is why the south does not trust the council to act in time. The lords of Shyona's southernmost province watched the last buffer disappear while their own confederation debated the cost of helping it, and the lesson their heirs took from it is the whole of southern politics now: that a frontier left to the council's deliberation is a frontier that falls. It is the grievance under Lord Norikane Sazagawa's decision, generations later, to stop asking the council at all and hire the Goldwatch to hold the wall himself. The Krell have not pushed north in force since Velkoron fell. The south does not believe that means they have stopped.