Kings were the leaders of many European states in the Middle Ages and Renaissance.
Kings are exclusive only in certain game modes of Age of Empires II and are available in the Scenario Editor. Kings are also available and seen in campaigns where they often represent historical characters. The Mongols encounter a King (the Khwarezmian Shah) in their campaigns; the Spanish meet two (Kings Sancho and Alfonso).
In the skirmish and multiplayer modes, Kings appear only appear in the Regicide game mode. Although they are weak and possess no attack, players that lose their King automatically loses the game. Kings move very quickly, and are useful for scouting in the early game, though it is extremely dangerous, due to threats such as wolves and enemy scout cavalry. Every player in a Regicide game begins with a castle, and a safer alternative to exploring with the king is to garrison him in it. Later in the game, they should always be kept behind walls or garrisoned inside Castles.
Kings, like heroes, cannot be converted.