Humanoid Cylons were a form of biological Cylon taking the appearance and mannerisms of human beings. Humanoid Cylons are noted for their remarkable similarity to human beings on a biological level, with only subtle chemical differences to highlight their synthetic design. Unless recognised by face, they could only be found out through testing of cremated remains or exposure to certain forms of radiation. Humanoid Cylons were capable of biological networking, and with the intravenous insertion of fibre-optic cables could connect to computers. If killed, Humanoid Cylons could transmit their memories into similar bodies in storage on a ship, in a process known as Resurrection.
The Centurions experimented with biomechanical engineering during the Cylon War, with human prisoners turned into Hybrids. The Centurions believed that by evolving beyond their mechanical bodies and into human form they would be close to God's chosen people. On the twelfth year of the war the Centurions were contacted by the final five survivors of the Thirteenth Tribe, a humanoid Cylon civilisation which had destroyed itself in a war with their own mechanical creations. Determined not to led the two civilisations destroy themselves, they pressured the Centurions into a truce. The Centurions would end their war with humanity in the Cimtar Peace Accord and settle on a colony of their own on the sole condition the five engineered a new race of humanoid Cylons.
Eight models of humanoid Cylon were made in all, each with their own appearances; personality traits and skills, and were then mass-produced with millions of each model. Around ten years after the War ended, the humanoid models, led by the Number Ones, overthrew their society, killing the five and installing telencephalic inhibitors to the Centurions, rendering them non-sentient slaves. In control of society and being subtly influenced by the Number Ones, the Humanoid Cylons' government voted in favour of breaking the armistice and continuing the war with the Colonials, though, in doubts over their ability to defeat them swiftly and utterly, moved on to infiltration. Using their humanoid appearances, these Cylons infiltrated Colonial society to gain information, taking on diverse roles such as Colonial officers; computer technicians; and businessmen tied to politicians. One Number Six was able to directly associate herself with Dr. Gaius Baltar, a computer technician in work with the Ministry of Defense for research into a ship navigation program, CNP, allowing her to modify the program to leaving a backdoor that could be exploited to disable any Colonial ship with its own programming. The plan was successful; the Colonial Fleet was destroyed, the Colonies themselves subjected to nuclear bombardment, and humanity was all but wiped out, except for a handful of survivors on the Colonies in outlying areas as well as a caravan of space-dwelling humans on ships such as Battlestar Galactica and on Pegasus, that eventually escaped the Colonial star system.
The Cylons continued to pursue the remnants of the Colonies, believing that humans would always seek vengeance against them.
The fundamental distinguishing aspect that differentiates Humanoid Cylons from humans is that their nervous system processes and transmits information rather differently. Because of this difference, the consciousness of a Humanoid Cylon has some of the characteristics of a computer software program. Their minds can be transmitted, stored, programmed and even interfaced with mechanical computer systems.
Humanoid Cylons are purely organic beings, yet they are still purely artificial. Humanoid Cylon DNA was in no way taken from any biological source whatsoever, but instead was entirely constructed—it is synthetic DNA. However, it was designed to be structurally compatible with natural human DNA to the point where a Colonial genetic test would identify Humanoid Cylons as humans. In fact, fundamentally, they are indeed human. Despite the fact that they consider themselves machines, the Humanoid Cylons are essentially a type of genetically manufactured synthetic humans.
Although they are purely organic, some of the protein structures of some of their neuronal metabolic pathways have molecular similarities to the silica pathways of mechanical Cylons. However, that is the only physical similarity Humanoid Cylons have with mechanical Cylons.
The bodies of Humanoid Cylons have stamina and strength slightly above the human average, and are designed to destroy or resist commonly dangerous human diseases, although they are not immune from all contagions. They are also heavily fortified to resist damage from intense radiation fields that would kill a human after short exposure, but they are still susceptible to damage from certain types of radiation or trauma. However, there are no further improvements on other characteristic design flaws of the human body. Despite their resistance to certain forms of energy, Humanoid Cylons, unlike the Cylon Centurion, cannot be made "bulletproof".
The Humanoid Cylon body is engineered with the ability to interface with a mechanical computer system or computer network. The cells on areas of the palms of a Humanoid Cylon were genetically encoded to have two types of subdermal cells with traits also unique to Cylons. One type of cell produces bioluminescence when stimulated by associated nerve cells (forming the "output" path of the interface Cylons use to interact with their technology). The other type of cell is similar to retinal cells and when stimulated by the proper wavelength of light, provides stimulus to associated nerve cells (forming the "input" path of the interface cylons use to interact with their technology).
To access and control Cylon technology, a Humanoid Cylon has to place their hands flat against a Cylon data-font (a data port into a Cylon central computer network). Doing that completes a biologically based optical data interlink between the Cylon and whatever it's interfacing with. That allows them to control equipment through a connection through the palms of their hands, up through nerve pathways in their arms, and finally, directly into the brain.
Because some Humanoid Cylon neuronal metabolic pathways have molecular similarities to mechanical Cylon silica pathways, they are susceptible to damage from the same types of radiation that would harm silica pathways.
A prominent aspect engineered into the Humanoid Cylons is "organic memory transfer"; upon "death", their consciousness is externally transmitted and downloaded into another Cylon brain of the same model line. This "resurrection" is limited by distance, signal integrity, and proximity to a downloading facility such as "resurrection ship."
As Humanoid Cylons are basically a type of synthetic human, they have genuine 'human' emotions with very real, very 'human' behaviors and personalities. It also means that Cylon minds react to stimulus in an identical manner to human minds.
Humanoid Cylons are susceptible to the same emotional traumas and joys that their human counterparts are. A case in point is a copy of Number Six, known as Gina Inviere, who was repeatedly physically and sexually assaulted by the crew of the Pegasus. These repeated assaults lead to Gina's near-catatonic state at the time the Pegasus discovered the Fleet.
The computer software-like consciousness of Humanoid Cylons enables them to create what they simply refer to as a "projection." Essentially an enhanced form of a self-induced and controlled hallucination, it's how they choose to see the world around them. Cylons choose the see their environment in any form they wish, whenever they wish. For example, if a Cylon were standing in a hallway, they could see it as a forest filled with birds, trees, and sunlight. The aesthetics is what gives them pleasure.
Humanoid Cylons even dream. However, they can be programmed not to need sleep.
All Humanoid Cylons share a collective knowledge base of data from other active or deactivated Humanoid Cylons of the same model, but within their model only. It is not of a collective consciousness "hive mind" nature. It's not automatic; they can choose to upload or download information. When they share information, it's visceral, they remember it very much like it was their own memory.
Including the Final Five, there are twelve active models of Humanoid Cylons, with the Number Seven model being extinct. Until recently, the so-called "Significant Sevens" had copies that numbered in the millions. However, there is now only one Number Three left and the Twos, Sixes, and Eights have been drastically deplenished in number as a result of the Cylon Civil War. The identities of these mechanized copies are determined by their model and each model is unique.
The original eight models created by the Final Five are based on archetypes determined by the Five that form what they perceived as the specific kinds of human behavior and personality, distilled into eight varieties. Each Humanoid Cylon has the same face, stature, hair, eye and skin color, gender, and other biometrics as all the others of his or her model. This point technically makes each copy a twin of itself, but there are some models that choose to make cosmetic differences. As well, the copies start out with the same basic personality, but grow more distinct due to their individual experiences. All the models except the Sixes have come to be associated with a particular "human name", and even other Cylons will refer to "Leobens", "Sharons", "Daniels", "D'Annas" and so on.
Although, like the other Humanoid Cylons, their minds' possess computer software-like properties and they are actually a form of synthetic life that did not evolve naturally, the Final Five as individuals were originally conceived and born through the process of biological procreation. As such, they do not exist as multiple active copies. That fact and their origin makes them fundamentally different from the Significant Seven despite the fact that they are genetically of the same 'race'.
- One - Cavil
- Two- Leoben
- Three - D'Anna
- Four - Simon
- Five - Aaron Doral
- Six- first model seen, e.g Gina
- Number Seven - Daniel (no longer exist)
- Eight - Boomer, Athena