The Military Leader, and in times of war, political leader, of the Republic of the Sphere.
The post and title of Exarch first came into being with the formal creation of the Republic of the Sphere with the signing of the Republic Formation Treaty between the 7th and 15th of March 3081. The first individual to be named Exarch was Devlin Stone, former head of the allied coalition against the Word of Blake, who was named to the office during the signing of the Republic Formation Treaty.
So far there have been 3 exarches in the history of the republic:
- Jihad: Final Reckoning, p. 61, "The Jihad in Review"