Talos is a robot on New Olympus.
Talos was originally built in 1290 B.C.E. on a rather simple level, compared to what he is now, by Hephaestus (the smith-god of Greek mythology) and Daedalus, the great craftsman, working together - perhaps also with the help of a Cyclops.  He accompanied the New Olympians when they withdrew to New Olympus, and continues to reside there, though he has been upgraded many times since then. 
When the Avalon World Tour brought Goliath, Elisa, Angela and Bronx to the island and Elisa was captured and put on trial by the New Olympians, Talos spoke in favor of making peace with humanity, on the grounds that it would not be long before their technology would be capable of breaching New Olympus' cloaking device; he was ignored, however. Not long afterwards, when Proteus escaped and attempted to overload the power supply for New Olympus, Talos came upon him and attempted to stop him, but was badly damaged by Proteus in his cyclops form. ("The New Olympians") He was repaired shortly thereater. 
When Terry Chung comes to New Olympus and the decision is made to make contact with the human world, Talos will serve as an advisor to Taurus (who will become the primary ambassador of New Olympus), joining Terry and Sphinx in their mission to the United Nations building in New York City and working towards peaceful relations with the human race. 
Talos currently looks much like an animated suit of armor, in the style of an ancient Greek hoplite. He seems to be nearly or entirely sentient and treated with some respect by his fellow New Olympians. While asexual, he is built to mimic the male form and personally identifies as male. 
- "The New Olympians" (First Appearance)
Real World Background
In Greek mythology, Talos was a robot made of living bronze built by the famous inventor Daedalus for King Minos of Crete, as a means of defending his kingdom from enemy fleets. Talos would regularly patrol the shores of Crete, keeping an eye out for approaching ships; when he saw them, he would throw rocks at them and sink them, then heat himself until he was red-hot and seize the survivors, burning them to death. He had only one vulnerable spot; the plug to the single vein of liquid brass that ran through his body, which was located in his heel. The sorceress Medea finally removed this plug through subterfuge, thus destroying him.
Talos also appeared in Edmund Spenser's unfinished epic poem, The Faerie Queene, as the squire of Sir Artegal.
Voice Actor: Dorian Harewood