Kage

Those who have achieved the title of Kage (literally "Shadow") are the leaders of the five most powerful Hidden Villages and generally (but not exclusively) the most powerful ninja in their respective villages. These villages do not rule the country, but are equal to the government. The Kage stand equally with the rulers of their countries, oversee the activities of their villages, and are the leaders of ninja society. There may be exceptions, however, as a ninja may be the most powerful at the time of being installed as Kage, but may become less powerful upon aging, eventually being surpassed by a younger ninja. A Kage may retire and give the title to someone else; however, once granted, the title is held permanently, creating a situation where a village has two Kage at the same time, with only one of them actually active. Their elite status is also attributed to the tendency for most Kage to have family members who were previous Kage, or be personally taught by a former Kage or student of a former Kage, or some combination of these factors. The five Kage have different titles depending on their country. Those titles are:
Hokage (literally "Fire Shadow") Kage of Konohagakure.
Kazekage (literally "Wind Shadow") Kage of Sunagakure.
Mizukage (literally "Water Shadow") Kage of Kirigakure.
Raikage (literally "Lightning Shadow") Kage of Kumogakure.
Tsuchikage (literally "Earth Shadow") Kage of Iwagakure.
The anime introduced a sixth Kage, the Hoshikage (literally "Star Shadow"?) from Hoshigakure (Village Hidden in the Stars). However, this was a self-given title and not officially recognized by the five other villages.