So kingdoms have royal buffs, but what about royal debuffs? Basically, I see it as a new royal structure or structures that would create debuff aura within a certain radius around it, in case the kingdom wants to punish a rebellious village, or extort something from them or whatever.
Some possible examples:
Famine - cuts the amout of seeds harvested by half, farm animals breeding rate is reduced
Plague - characters in the area have a chance of spontaneousely getting infected sores, also wounds heal slower
Devastation - objects decay 2 times faster then usual, even on claimed land(personal or village claim), also wild agressive animals can spawn on claimed land