In the decades prior to the First Cylon War, the Caprican Marines are part of an effort by the Caprican Government for the creation of a robotic army. Marine personnel are present during early testing of Graystone Industries' U-87 Cyber Combat Unit, marking their involvement in the creation of the first Cylon in the Twelve Colonies (CAP: "Pilot").
Some time later, the Caprican Marines are called upon to pursue the Cylon prototype as it escapes from Graystone Industries' labs and drives into the outskirts of Caprica City in a stolen van. Deploying a VTOL aircraft (alongside a Caprican Air Force Phoenix), the Marines are ordered to track, but not engage the Cylon - ultimately observing from above as the van containing the robot soldier collides with a military roadblock and explodes (CAP: "End of Line").
Despite the debacle with the prototype U-87, Graystone Industries under the control of Tomas Vergis begins production on the military's order of 200,000 Cylon soldiers and beings delivering them to the Caprican Marine Corps (CAP: "Unvanquished").
Some months later, the some of the delivered Cylons are outfitted with Marine armor and emblems and assigned to aircraft. Exploiting backdoor access, Daniel Graystone commands a squadron of Marine Cylons to land their VTOLs in Atlas Arena and engage a group of Soldiers of the One as they attempt to bomb the stadium (CAP: "Apotheosis").
- The aircraft flown by the squadron of U-87s in "Apotheosis" are marked both with "Marines" pennants and the distinctive pentagonal shape seen on the Cylon War-era Raider in flashbacks to the war in "Razor". This suggests a link between Caprican technology and that used by the Cylons, indicating that the Cylon Raider was possibly of Caprican origin.