Harka was an Elite who served as a military assistant to the Prophet Hierarchs during the early years of the Covenant Empire and before the Human-Covenant war. His rank is unknown, but appears as a swordsman and likely high ranking. Harka served as the main antagonist of the Halo Legends episode: "The Duel".
Upon hearing that Arbiter Fal 'Chavamee had been declared a heretic by the Prophets, Harka sought hunt him down and usurp him.
Towards the end, Harka dueled Fal in an attempt to defeat and kill him. Harka mortally wounded Fal who eventually died, but Harka was stabbed with Fal's Energy Sword and died first.