Each leader has both a unique ability (which gives him or her special bonuses and gameplay advantages) and an agenda (which affects how he or she plays the game and interacts with other players when controlled by the AI). Some leaders' unique abilities allow them to unlock unique units after researching specific technologies. In vanilla Civilization VI, there is one leader for each civilization (except the Greeks). However, it has been confirmed that future downloadable content and eventual expansions for the game will include multiple leaders for each civilization.