So let’s talk about Cylons. The original concept of Cylons in Battlestar Galactica started out as an advanced reptilian race of aliens who created the robotic race also called Cylons, to serve them. The Cylons were on a galactic quest of domination and were attacking the Hasaris who turned to their friends the humans of the 12 colonies and they got caught into the war. After the Hasaris were wiped out the Cylons and the humans were at war for 100 yahrens during which the reptilian race died out centuries earlier, presumably destroyed by their own creations, leaving behind only their race of robots.
The Cylons are ruled by an Imperious Leader most advanced Cylon model. Under him are several IL series Cylon robots, who look much more civilian. However the Imperious Leader has a reptilian body, shaped much like the original Cylons masters and 3 brains. Each time the IL is destroyed, his consciousness is downloaded into an identical body and carried on (this concept was carried forward to great effect as a characteristic of every human Cylon in the rebooted series). IL-series Cylons act as commanders for the military and governors for civilians of the Alliance. They have two brains, and a mostly transparent head through which various lights can be seen pulsing. They also have a metallic, humanoid face with two eye scanners (compared to the single eye scanner of the Centurion models), and wear clothing (full-length glittering robes).
Command centurions look like the regular centurions only with gold armour. These are the lower commanders for individual military units, though they can be responsible for entire Basestars and garrisons. Their voices are slightly lower pitched than regular Centurions. And ofcourse you have the regular military centurions, androids with silver armor. Centurions are armed with a powerful energy weapon, often referred to as a blaster rifle. They also have bayonets and swords for close combat and the execution of prisoners. Although not common, some of the Centurions are given names. There is also a unique Cylon with glittering robes, with a metallic humanoid face, called Civilian Cylon. They are only seen in one episode.
And finally we have the briefly seen humanoid Cylons – a rather new model probably first built long after the destruction of the Twelve Colonies of the Humans. They are only seen in the Galactica 1980 episode “The Night the Cylons Landed“. One of which is named Andromus. Though it is entirely mechanical beneath its artificial skin, this model is an android and has a superficial human appearance (and a condescending attitude toward Centurions). Once again, this concept was taken to full fruition in the rebooted series, who ran with this concept to great effect. Ofcourse the concept owns their origins to the original Galactica 1980 although they improved on it.