Ord Casto (Earth-2042)

"Whosoever is gripped by fear, take heed. I am the Prophet of Truth... And I am not afraid."

- High Prophet of Regret

The High Prophet of Truth, born Ord Casto and formerly serving as the Minister of Fortitude, was a male San'Shyuum and the most prominent of the three Hierarchs who ruled the Covenant High Council during the Ninth Age of Reclamation. After pledging the loyalty of the Covenant to the Confederacy of Independent Systems, Truth and his fellow Hierarchs were made members of the Separatist Council. Cunning and ruthless, Truth oversaw the Confederacy's genocidal campaign against the Galactic Republic for four years in a massive war. Truth also orchestrated the sudden expulsion and attempted genocide of the Sangheili during the final year of the war. This betrayal against his people would ultimately lead to his death in late 20 BBY.

Source
https://www.halopedia.org/Prophet_of_Truth