Combat drills were mining vehicles used as attack vessels in the Shu-Torun Loyalist/Imperial Delving Fleet on the planet Shu-Torun. During the War on Shu-Torun, the Sith Lord Darth Vader rode in a combat drill with his stormtroopers, but his supposed ally Doctor Cylo sabotaged the vehicle and caused it to veer off course into a lithoporoite seam which was not strong enough to support the drills weight. The drill therefore fell into a cavern below the seam, where it was ambushed by troops working for Cylo-V and the rebellious Baron Rubix. Vader's troopers were able to defend the vessel with the aid of a squad of modified BX-series droid commandos also stored onboard the drill and eventually return to the true conflict.