A fey spirit masks itself as a bee which investigates all who travel within a specific section of the forest. Any the bee finds worthy are allowed to see the hidden opening into the fey kingdom, just off of the trail. Any deemed unworthy see only the bee, buzzing around around them momentarily before moving on.
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.