The High Chancellor is the head of the Elder Council, a group of advisors that aid the Emperor, who is appointed by the Emperor himself. In the absence of an Emperor, the High Chancellor is the de facto ruler of Tamriel, and is normally the second-highest authority figure in all of Tamriel, naturally only second to the Emperor. The position has existed ever since the establishment of the Elder Council during the First Age.
High Chancellor Ocato, an Altmer, held the seat of High Chancellor during the late Third Era, and during the Oblivion Crisis. High Chancellor aided the Hero of Kvatch and Martin Septim in bringing about an end to the Oblivion Crisis at the end of the Third Era. After the Oblivion Crisis, he can be found in the Imperial Palace. He rules Tamriel with the help of the Elder Council as a de facto ruler in the absence of the Septim bloodline. He is always an essential character.