They could only be constantly worn down by the other side, and there's no way to completely obliterate them.
If this situation continues to drag on like this, there's a fear that the circumstances will soon turn extremely unfavorable.
After all, these super top-tier factions occupy only a very small portion. This time, the invading forces in the Chaotic Sea Domain, those ordinary forces are the real mainstream, taking up the majority of reinforcements.
If they let that Undead Force continue to harm those ordinary forces, by the time those ordinary forces fully withdraw from the Chaotic Sea Domain, it will probably be when that Undead Force gathers its strength to confront them head-on.
By then, just these super top-tier factions, even if they unite, will be unable to confront them directly, unless their homeland is willing to send reinforcements regardless of the cost to assist them here.
But that's obviously impossible.
