[Butz]

Now, not that there have actually been any wars lately, but just in case there are, I think something like this should happen.
First off, in addition to the kingdom status of "Allied" "Neutral" and "Enemies" there should be an "At War" status.
If it's possible, when two kingdoms are at war, anyone in Peaceful mode stays in Peaceful, but when attacked by a member of the opposing kingdom, takes damage normally. If your kingdoms are at war, and you are killed by a member of the opposing kingdom on their island, you should be sent to a prison area. If you are killed anywhere else in Graal, you should be sent back to an infirmary on your own island. After the war has ended, all patients can be released from the infirmary, and then the Kings can negotiate for the return of prisoners.
It's much harder to rush back out into the fight when you're in jail or in a hospital. ^.~

Anyway, just an idea.