“ A kingdom where, if there are multiple princes (princesses can't rule unless they have no siblings), the princes fight to the death in the arena to decide who gets to rule. A simple way to make sure your brother cannot make a bid for the thrown, and keeps the royal blood in one line.”
“ All estates, manors, castles, fortresses, and palaces are required by the King's Law to be converted into civilian shelters in the event of national emergency such as a disaster or attack. This includes the Royal Palaces. It is an act of treason to fail to comply such an emergency order.”
“ It is traditional for two warlike countries to each give their first-born royal prince as a hostage to each other to prevent war. One of the princes has been murdered, and the PCs have a few days to rescue the prince in the other country to save him from being executed and a bloodthirsty war from breaking out.”