Arbiter is a fictional ceremonial, religious, and political rank bestowed upon alien Covenant Elites in the Halo science fiction universe and the rank is given to a disgraced commander as a way to atone for his failures. Although the Arbiter is intended to die serving the Covenant leadership, the High Prophets, he survives his missions and the Prophets' subsequent betrayal of his kind. When he learns that the Prophets' plans would doom all sentient life in the galaxy to extinction, the Arbiter allies with the Covenant's enemies—humanity—and stops the ringworld Halo from being activated.