The official who administers the Klingon Rite of Succession and confirms the new leader of the High Council, an office K'mpec entrusts to Captain Picard.
The Arbiter of Succession presides over the rites by which a new chancellor of the Klingon High Council is chosen. The arbiter decides which form the ritual takes, rules on the claims of the challengers and finally installs the victor.
In The Next Generation episode Reunion the dying K'mpec summons Picard and gives him the task. He does so because he has been poisoned and trusts no Klingon to act fairly. Picard oversees the Sonchi, revives the ja'chuq, and investigates the bombing that follows.
The duty continues into Redemption. The Duras sisters produce Toral, an illegitimate son of Duras, as a rival to Gowron. Picard rules that the boy has no claim, a decision that is correct in law but starts the Klingon Civil War. He then installs Gowron and insists that the Federation take no side.