There is an important pair of fraternal twins. Possibly minor dieties, sorcerers, or maybe just an important pair of nobles. One is evil and one is good. The thing is, the one who looks evil at first glance is the good one, and vice versa.
There is a person who has a well-known reputation, probably involving something illegal. But this person is either very clever and crafty, or really like his or her privacy, for no one knows who this person actually is. As an added twist, perhaps this person is of an age that would noramlly be wildly inappropriate (say, a child is a much-feared bandit) or maybe not the expected gender or even race.
One of the most wanted assassins in the realm looks exactly like an important person (local nobility, PC, etc.) This may or may not be common knowledge.
There are those as rich as kings but dress as peasants and worry not about funding. To visit their true homes one would see wealth of untold value scattered as dirt is in a hut. They know the monetary value of their possessions but they have long lost any true value to their owners. Experience is their currency and their curse. They dispense secrets of the ages as if discussing the weather. Few things have they not experienced so that very little gives them joy. They are the lost ones looking for new life while humoring the mortals around them.
Whistling on the sea is bad luck. It is said to mock the sound of a strong wind and will call it so nature can show the true sound. Whistling is only allowed when becalmed or when shrouded in fog.