Android/Humans

Synthetics (Synths) are androids which are designed to assist humans in menial and daily tasks. The first synths were created by David Elster, Prof. Edwin Hobb and Dr. George Millican among other scientists.
== Appearance, Behaviour, and "Biology" ==
They can be distinguished from humans at a glance by their unnaturally coloured eyes. Upon creation, unbonded synthetics have light blue eyes. Upon bonding with a primary user, their eyes turn an unnatural shade of green. Upon death, their eyes lose all colour and turn a dull grey. In addition, every synthetic has their serial number imprinted onto their iris, which can be read with a special magnifying glass. The voice of a synthetic is typically similar to a human's, however if electrified the synth's voice modulator produces more unnatural tones and sounds, suggesting that a synth's voice is not set in stone. Also, most synthetics can speak many languages, with the exception of models that may not need speech, for example industrial or mining models which are thought to only be capable of speaking its native language. A synthetic's power button is under their chin, and upon startup they play a musical chime. Further, a synthetic can put itself into a hibernation-type mode where they conserve energy usage and become dormant, although they can still sense what is happening around them to some extent. Synthetic fluid, sometimes referred to as their "blood", is a deep blue colour. It is said to have healing properties when mixed with human blood, and according to V, is able to modify human DNA in ways that pass down to children. Synthetics can also be given directives other than to serve their primary user, such as when Niska escaped from imprisonment - all regular synthetics were given the order to report her position to the Metropolitan Police should she be spotted.
After Day Zero, the green-eyed synthetics who were given consciousness were replaced by the "11th generation" synthetics created by Lundstrom, known colloquially as "orange-eyes", fittingly for their firey orange-coloured eyes. These 11th generation were immune to the program that gave synthetics consciousness, making them fit for human servitude. These synths also have the ability to integrate with the user's smart home technology, allowing them to control various appliances to help serve their primary user better.
== Conscious Synthetics ==
David Elster, after his part in creating the first synthetics, wanted to push towards giving them consciousness and the ability to think, feel, and want. The other scientists were not too keen on this idea, so he was forced to work on his own. The first prototype given consciousness by David was Mia, who was created to help raise his son, Leo Elster. She was later followed by Fred, made to be a brother to Leo, Niska to be a sister, Max another brother, and after David's wife Beatrice Elster committed suicide, a synthetic identical to her was created with an executive block to harming herself, which later became Karen Voss. Pieces of a larger program were hidden in the root code of the prototypes which could be pushed as a software update to regular synthetics, giving them consciousness after a while. This code was pushed to all synthetics by Niska at the start of season 2, but it didn't take effect immediately because of the time restraint. The code was later optimised by Mattie Hawkins, to the point where it would give consciousness to any synthetic, instantly. Mattie's version of the code was pushed to all synthetics again at the end of season 2, starting "Day Zero", and setting off the synthetic revolution.
== Day Zero ==
After the "Day Zero" where all synthetics were given consciousness by Mattie's software update, most of them were forced into a round 200 "designated areas" which kept them contained (such as The Railyard led by Max), comparable to refugee camps. Chaos was caused by this update, and an estimated 110,000 human lives were lost along with over 100 million synthetic lives (according to Agnes). The synthetics affected by this update were labelled "anomalous", and subject to extreme discrimination and prejudice from humanity, with children being taught in schools that green-eyed synthetics are dangerous because they are not subject to humanity's will. After a terrorist attack by a radicalist synthetic, public opinion turned almost entirely against synthetic rights, leading to a string of anti-synthetic terrorist attacks, and a nationwide curfew for "anomalous" synthetics. However, it is mentioned at the Dryden Commission that in the Scandinavian nations, integration with the newly-awoken synthetics is being trialled.
== Trivia ==
* Lundstrom, the company that created the orange-eyed synthetics, is named after Lars Lundström, the creator of the Real Humans show that originally aired in Sweden that the show is based on.
* Green-eyed synthetics seem to have the capacity to change their eye colour, as is seen with Niska's eyes changing to purple after being connected to the internet, although this seems to be entirely involuntary.
* According to Niska, the code that gave green-eyed synthetics consciousness was 17,000 pages long.