Warren Clavain was Nevil Clavain's older brother. Warren and Nevil were both senior military officers of the Coalition for Neural Purity, stationed aboard Deimos to monitor the Coalition's quarantine of Mars -- which had long been under the control of their enemies, the Conjoiners. The war with the Conjoiners left Warren with only one eye, having lost the other and sustaining other severe injuries in combat with the Conjoiners and with the robotic worms on Phobos.
Their differing experiences in the war led Nevil and Warren to fall into a dispute just as Nevil was about to make a diplomatic visit to the Conjoiner headquarters. Nevil believed that any peace, even a temporary one, was worth striving for; Warren believed that a war that was inevitable should be fought immediately, while the Coalition still had the advantage. Because of this divide in philosophy, Warren later fabricated evidence that Nevil was massacred by the Conjoiners upon his arrival on Mars surface, as an excuse to resume hostilities. Because of this, Nevil lost what remaining attachment he had to him, and eventually decided to join the Conjoiners' on their interstellar journey aboard the Sandra Voi.
- Warren was last seen secure in his position among the Coalition leadership, but what effect his manipulations had to his career is unknown. Galiana appeared confident that the Demarchists would eventually see thru his deception.