Come! Enter into the safe haven beneath the seas! Where humanity fled from the deadly Kalleum bombs! Take Refuge Beneath the Waves.
You think the zombies are bad? Wait till you meet their masters!
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.