The Dark Fool was more commonly recognised as a court jester; the idiot and the entertainer of the mediaeval, royal or baronial halls and castles.
In the Middle Ages, the fool was, paradoxically, the most privileged and most clever of all the members of the Royal court. His entitlement to go anywhere unchallenged and unheeded, and behave however he wished without question, gave him enormous insight, power and influence. Contrary to his half-witted appearance, there was nothing about which the fool did not know or understand