The Cylon Raider is the standard starfighter used by the Cylons, in the various Battlestar Galactica movies and television series. Cylon raiders are used as the main line of defense for Cylon Basestars.
The Raider in the original series is an exceptionally powerful fighter/attack craft employed by the Cylon Empire and carries much more formidable armament than the weapons on Colonial Viper fighters (two directed energy weapons and provisions for internal bombs). A Cylon Raider carries a crew of three centurions (commander, pilot and co-pilot). The commander sits on a slightly elevated seat between the two pilots and issues orders. Raiders frequently make suicide attacks on enemy capital ships, typically attacking the fighter launch bays. Although a typical Basestar holds far more Raiders than a Battlestar has Vipers, this advantage is often negated by the human ability to improvise and adapt to changing combat situations. In the episode "The Living Legend", Baltar commissioned a personal fighter to take part in a battle. It is used to transport him (not unlike Colonial shuttles).
The original series' Raider made an appearance in the reimagined series vignette Battlestar Galactica: Razor, though slightly altered in appearance, and piloted by centurions very reminiscent of the originals.
A larger 'super' raider was depicted in the sequel series Galactica 1980. It was called the "AB Raider".
Battlestar Galactica (2003, 2004–2009)
In the 2003 reimagining of Battlestar Galactica, the Cylon Raider is the main attack fighter used by the Cylons, participating in the destruction of the Twelve Colonies and later actions.
This fighter is very different from the previous, piloted Raider used during the Cylon War (the Raider from the 1978 series). The new Raiders are cybernetic in nature: the ship is actually a living creature, with a complex system of organs, veins and biological fluids inside the main body. Just like the humanoid Cylons, the Raiders are also capable of being "reborn" into new Raiders after having been destroyed. This is done so that new, replacement Raiders do not have to be trained, meaning that experienced combat "pilots" that have been killed are quickly available for duty again. This provides the Cylons with a distinct tactical advantage in the amount of battle-seasoning a Raider will have over a replacement Viper pilot; in essence, every time a Raider is destroyed, it is reborn slightly improved having "learned" through each Death/Downloading/Rebirth life-cycle it undergoes. Raiders can also perform riskier, but more devastating attacks on the Colonials, including but not limited to, kamikaze-style attacks.
The Raiders have many weapons, including conventional and nuclear missiles as well as kinetic energy weapons. They can transmit acomputer virus to a Colonial vessel using the Command Navigation Program (CNP), rendering the Colonial vessel inoperable. When transmitting the virus, its red eye activates and oscillates to the left and right repeatedly.
The Cylon Raider is also capable of making FTL jumps. After a Heavy Raider was captured by the Battlestar Galactica, its FTL drive system was discovered to be more efficient than those on the Colonial vessels. It could travel the distance of Kobol to Caprica in less than 10 jumps (compared to the estimated 120 jumps the Colonial fleet would take). It is capable of atmospheric flight, as was its predecessor, and is far more maneuverable in spaceflight than the previous Raider, likely due to upgraded thrust-vectoring systems.
Sharon Valerii has stated that the Cylon Raiders are very much like trained animals with basic thought and survival instincts. They also feel pain and trauma in the experience of death.
During battle in the episode "He That Believeth in Me", a Raider scans a Viper piloted by Samuel T. Anders. The Raider, possibly believing Anders to be one of the Final Five Cylonswithdraws, along with the other Raiders who refuse to fight. This act leads the Twos, the Sixes, and the Eights to believe the Raiders have developed free will. The other models believe the Raiders have exceeded their original programming and vote, along with a single Number Eight, Boomer, to have the Raiders reconfigured back to their basic mode. The Twos, Sixes and other Eights protest vehemently and in retribution remove inhibitor modules from the Centurions, effectively giving them independent thought. The Centurions become angered by what the other models have considered the lobotomy of the Raiders and seek retribution on the models who voted for it.