Robots are a race of living machines that were created by the Human Race. They ruled over them for a short time after both races realized eternal life. After the Ruin began, both races were placed on the same social standpoint.
Robots were machines originally created and built by humans. They can vary on appearance depending on how they were built. Robots are immortal in the sense that they do not die of age, though they can be killed or rusted to death by water. At one point in history, Robots rose up to power and ruled over the human race led by the emperor, Braiking Boss.
After the Ruin began, Braiking Boss stepped down and the Robotic race would ultimatley be brought to the brink of extinction. The Ruin caused the metal that created their bodies to be filled with iron-oxide which would cause them to quickly rust and crumble, killing them. Robots at this time had a natural hate for humans, most were brought the the edge of insanity and believed in any rumor they could to be saved.
After the Ruin, Robots were classified into groups depending on their appearance and actions.
BanditsBandits are described as marauding Robots who attack and threaten anything in order to get what they want. Most of them are either insane or evil thanks to the desperation caused by the Ruin. Bandits normally abuse the other classifications of Robots. Bandits are normally described as oddly shaped, normally not having a large, mishapened body or an awkwardly deranged small body.
HumanoidsHumanoid Robots are rare Robots who have experienced little or no Ruin on most of their body in order to maintain a human like appearence. Normally these robots are far less common, they are also normally more skilled in combat or intelligent then Bandits. They have human shaped bodies and human looking faces with the exeption to replaced parts due to the ruin.
UncategorizedThere are some Robots on the planet who do not quite fall into the Bandit or Humanoid Cateogory. These robots are usually small in size and are shapped in that of a humanoid but can have clearly robotic faces and parts on them, probably due to the Ruin. For example, Rune used to look much like a Human before the Ruin and currently he looks as if he could be a bandit.
Robots are machines composed of different metals and possibly covered by skin (in a humanoids case). They are run by an unknown energy source but it has been stated that they have "hearts" and also some Robots have even been shown to bleed while others spew oil when damaged.
Robots do not require to eat or drink though they can experience fatigue and therefore need to rest on occassion. It is inferred that most robots are built small to signify that of a human child and can physically grow into an adult body (EX: Ringo).
All Robots are immune to disease and infection that humans can catch, all though Robots can build up iron oxide in their bodies causing their bodies to rust and decay. Besides the effects of the Ruin, a robot can rust due to an outside source of water such as Rain after an unknown period of time. 
Robots most obsolute feature compared to that of the Human race is there inability to reproduce using their own cells, making it impossible for them to expand their race after the Ruin.