Cylon Types

Contrary to popular Colonial belief, there are other types of Cylon other than the standard silver Centurion. Breaking the belief down even further, most Colonials do not actually recognise the fact that there are Cylon Drones and Cylon Citizens!

So, there are actually six types of Cylon - Drones, Citizens, Silver Centurions, Gold Centurions, IL Series and the Imperious Leader himself.

The Cylon:

A Cylon is, at its basic level, a bipedal robot. They are self aware, and usually quite logical. They are not especially fast, but they are quite strong. They are obviously artifical in nature, and most Cylons are larger than a human - around 6' 6", although this varies with their type. Cylon eyes glow red, and pulse back and forth. Originally this was thought to be some kind of radar system, but this has since been disproved.
A Cylon is powered by internal powercells which allow it to function without outside aid for around nine to ten yahrens.

They have standard human style sensors (audio and visual), and they also have the ability to detect certain basic emotions in humans, such as anger, hatred, fear, happiness etc. This is probably due to their sensors picking up on the physical characteristics of emotions (sweating, crying, shifty eyes etc) rather than any psychic ability, but it can be used to unnerve humans at moments. It was probably developed as an aid to interrogation.

The big thing with Cylons, is that they do not function well as individuals and tend to be slow witted if their link to the Information Network is disrupted.
Cylons do have some other disadvantages as well. They lack speed and mobility - the fastest a Cylon can go is the equivilant of a human jog. It is easy for a human to outrun a Cylon - just not last them out. Most Cylons also have a large amount of skills, but these skills are hardly ever as good as a human. A human can learn, a trait that, while present in all Cylons, is rarely used in most.
While most Cylons are also armoured, they are still subject humidity and dislike hot and wet areas. The water vapour can get inside of a Cylons circuits causing long term rust and problems.

Emotions:

Cylons have emotions. Centurions hardly ever show these (a wasted trait in warriors), but even they have some. They can show fear or apprehension by a rapid pulsing of their eye. This is only done in times of great stress (so most combat situations do not count, even when the Cylon is sacrificing his life), and an example would be when a Cylon is protecting a more important being, and a threat that they cannot cope with appears. As well as emotions, they have other traits such as the ability to concentrate. Not a very common thing for a Cylon to do as it involves the Cylon using all its brain power to a specfic task (such as a stand-off fast draw pistol duel), and when this happens sometimes the Cylon eye stops as the time of greatest concentration.

The IL Series show emotions just a bit more, mainly survival traits though which allow them to lie, deceive and get out of dangerous situations. They can also show jealously and ambition.

Cylons have the ability to detect certain basic emotions in humans, such as anger, hatred, fear, happiness etc. This is probably due to their sensors picking up on the physical characteristics of emotions (sweating, crying, shifty eyes etc) rather than any psychic ability, but it can be used to unnerve humans at moments. It was probably developed as an aid to interrogation.

Drones:

At the lowest level of the pecking order, live the Cylon Drones. These Cylons are below citzens in rank and status, although in appearance they mirror them. Their function is as the basic worker of Cylon society. They have only limited programming - just enough for them to be able to do their tasks without supervision. They have no combat abilities at all, no real initiative and just enough intelligence and education to fufill their roles.
Drones have one brain, but as stated, it is very limited.

Citizens:

Next, comes the citizen Cylons. Hardly anything about these Cylons is known as most humans only tend to come into contact with the Centurions. Citizens are the the backbone of the Cylon Empire. They deal with the mundane tasks, the administration and the running of the Empire, and most things non-military.
Whilst they can operate military weapons (and some work in military bases), they are generally the weakest of the Cylons and the most non-combative. They are never seen in intentional combat situations, and thus will never be found in Baseships or Raiders.
Civilian Cylons have only one brain, but are limited to what they can do with it. Whilst they are not as limited as Silver Centurions in that they required supervision, they cannot access any combat related skills that might be normal for other Cylons.

Centurions:

The Centurions are all Combat Cylons. Their bodies being tougher than other Cylons, and they have combat abilities and weapons training. Whilst ranking exist betweem Cylons, all superior ranking Cylons refer to Centurions simply as Centurion, without stating the lower rank. Centurions do not use figure of speach, stating what they mean.

Silver

The standard Cylon warrior. Not fast, but strong and able. Follows orders without question and regard for its own being. They are all ground troops and fighter pilots.

Whilst not having many rankings, silver Centurions do have some ranks and system of grading amongst themselves, the most common being that of Flight Leader who commands a patrol of fighters (8 fighters or about 24 Cylons), and just above that is Group Leader who can command a lot more, and is the intermediary step between Silver and Gold Cylons.

Silver Centurions have one brain with which to interprete orders, which gives them a very limited choice of actions, and thus they require supervision. They do not have much in the way of individualism. Silver Centurions do not have names. With the information network, it is always clear to whom a command is being directed to. Only Flight Leaders or Centurions with rank have a designation, and then it is a number, such as Flight Leader 17.

Gold

Command Cylons or called "First Centurions" by the Cylons themselves. Fairly rare, but able. A leader model, referred to as a First Centurion by the Cylons themselves, with one able to command a Baseship. Follows orders from IL and above Cylons.

Gold Centurions have two brains, and thus they are very capable machines. They do not require any sort of supervision, and can make and act on decisions themselves. This second brain is filled with military information and knowledge and not a lot else, making them not too effective outside of this field. First Centurions do not have much in the way of a personality, but unlike Silver Centurions, they do have a simple name.

IL Series:

Command and Supervisor Cylons: Intelligent, able to reason, lie and deceive (even to other Cylons). They may command Baseships and other installations.
This series of Cylon has been upgraded over the years, and more modern versions tend to view themselves as more superior than their early brethren. As stated, they have the ability to deceive, and this does include to other Cylons if it would mean them saving their necks. This may be the reason why no one knew of the Battlestar Pegasus being in the Gomoray system attacking the Cylons. The IL series however are not combat Cylons, and it is doubtful whether one has ever raised a weapon in a combat situation.
The IL series of Cylon have two brains much like Gold Centurions, although like their brains, the IL series have a wider range of knowledge and information available to them. Whereas the Gold Centurions have information about leadership and miltary matters, the IR series has a very flexible and wide ranging choice of actions. It is this variant second brain that allows them to develop more human emotions and traits. All IL Cylons have a name.

IL cylons function in a variaty of roles, mainly as advisors and executive officers to First Centurions or other Cylons.
First Centurions and IL series Cylons can become Warriors of the Elite Class. This is rewarded for extreme tactics and heroism, bravery and outstanding sucess. It is not a common award, and the Cylon really has to work for the award, which means against the Colonials, the Cylon has to try and think like them, ironically an act which they despise.

The Imperious Leader:

The only Cylon to still resemble the old Reptilian beings, although these are definitely robotic. Nothing is known of their combat abilities. The Imperious Being is the leader of the Cylon Empire. And that is about all that is known. When one is killed, another is selected, although if one is built specifically or whether another Cylon is chosen, or if indeed more Imperious Leaders exist in a separate location is also unknown. All Cylons obey without question though.
The Imperious Leader has three brains, which gives it much more knowledge and experience on nearly all matters concerning the Cylon race, including history, warfare and more. With their unrestricted access to the Information Network, an imperious Leader knows everything there is to know about the Cylon race and Empire.

When an Imperious Leader is replaced (which is after 75 yahrens or when the Leader gets killed in duty), the replacement is always an IL series. What happens to an imperious Leader after their term of duty is unknown.