Tartarus (Earth-2042)

"The Great Journey has begun, and the Jiralhanae, not the Sangheili, shall be the Confederacy's escort!"

- Tartarus, to Arbiter Thel 'Vadam

Tartarus was a male Jiralhanae and the last appointed Chieftain of the Jiralhanae and military chief to serve in the Covenant and the Confederacy of Independent Systems. He acted as the Hierarchs' chief enforcer and, more accurately, the High Prophet of Truth's second-in-command. Tartarus was responsible for enforcing Truth's changes to the Covenant which caused the Great Schism, the civil war that led to the military downfall of the Separatists and the dissolution of the Covenant. In the final weeks of the Clone Wars, Tartarus attempted to activate Installation 05 to begin the Great Journey, but he was ultimately killed by Arbiter Thel 'Vadam with the help of Jedi Knight Anakin Skywalker and Sergeant Major Avery Johnson.

Source

 * https://www.halopedia.org/Tartarus