Cavebreaker first came to the attention of the Resistance as an individual human host Scourge in apparent command of one of the few deep cave raiding parties to reach the depths where resistance fighters were based. He was notable for his obvious combat prowess and extremely dark eyes, so black that most guessed that his body had been modified by the scourge.
Much later, one of the few who survived Cavebreaker's raid witnessed a striking similar individual boarding a modified Annihilator construct, which appeared to have an actual crew compartment - a rare things to see. Today Cavebreaker still lives up to his name by utilising a special modified Annihilator to rain down sustained barrages of plasma, cutting through to the deep places on Eden Prime and bringing agonising death to any unfortunate souls cowering there with no escape route.
Complete rules and background for Cavebreaker can be found in Reconquest: Phase 1