Hello! The suggestion is simple, but it would add very, very fun to players.
The main idea is only make it an entertainment challenge. No need rewards, perhaps only an amount of gold or anything else.
The períod of this war should be shorter, perhaps 24 hours. An alliance should declare war to another and the challenged alliance should have 12 hours to decide if accept or not. Once accepted, the war is declared and it begins 12 hours after.
What do you guys think? It would start a flame challenge in royal!