The Fool in fact is not a role, or the fool can be anyone, any role, any status. However it is possible for a professional fool to don a costume that makes him/her recognisable to an audience, clown and jester are the more common western images that let people know that it is OK to laugh a this persons misfortune. Some Fools like Keaton and Chaplin, developed their own “trade mark”, while others are known by reputation, by their acts: John Lennon staying in bed, Ghandi fasting, Einstein asking impossible questions, Jesus preaching love is the way.
The fool is staying true to ones self, even if it makes one look like an idiot as one goes against the tide of normality.
The role of the fool is to warn us when we are acting like lemmings, following a normality that is straying from our nature. The fool was the only member of the court that the king or queen could trust, as he had nothing to gain by lying and manipulating, as fools only want to be self empowered, they are not interested in gaining power over others.