Bessus

…The senior nobles accompanying him, led by a powerful provincial governor named Bessus, who commanded the eastern territories, had concluded that their king was a liability who kept losing, and that their best hope of survival, or perhaps of seizing power for themselves, lay in taking matters into their own hands.…

…Bessus actually tried to claim the Persian throne for himself, taking the name Artaxerxes V and retreating into Bactria, the northeastern frontier province of the empire, centred in what is now Afghanistan and Uzbekistan.…

…He's just captured the regicide, Bessus.…