Dr. Zeus Inc., also known simply as the Company, is a fictional entity in a series of time travel science fiction stories by Kage Baker. Most of the characters in the novels are immortal cyborgs created by Company operatives throughout history and recruited to work on preserving art, artifacts, rare species and other valuable items which the Company can sell for huge profits in the 24th century. The cyborgs look forward to receiving their final reward when they reach the 24th century by living through all the preceding times, but some suspect that when they do, they will instead be deactivated, or worse.
The immortality process, taking place as it does in early childhood, results in an individual who matures into a young adult and remains that way forever. "Facilitators" resort to makeup and prosthetics in order to appear to be older for their roles, but others appear as they always have. The Botanist Mendoza, for instance, appears to be approximately 19 years old despite having lived for thousands of years during her life and exile in the distant past. Joseph is described as "seeming to be about 35" (The Graveyard Game), indicating that Facilitators may have their "natural" ages set higher for their roles.
Preservers
Preservers are the main agents of the Company, specialists in different types of artifacts. They look exactly like normal humans, but small differences give them away to observant individuals. Typically a Preserver uses a credenza, which apparently is a piece of data processing, or analytical, equipment suited to their work. When among mortals, the Preserver can conceal the credenza, if necessary, by "merging" it with a piece of ordinary furniture (as Mendoza does in In The Garden of Iden). The technology behind such tricks is not explained in any detail, if at all.
Mendoza
Mendoza is a female cyborg, a botanist recruited from the dungeons of the Inquisition in 16th century Spain. In appearance, she is a barely adult woman with flame-red hair and startling black eyes. While still chronologically young, she suffers a huge psychological trauma after falling in love with a doomed mortal in Tudor England. She is also a "Crome Generator", with a powerful psychic potential that she cannot control. Through a series of awful events over the following 300 years, she comes to despise mortals, her fellow cyborgs, and eventually herself. She attempts to isolate herself from all harm, but cannot escape the Company, for whom everything she has done and will do is in the temporal concordance.
Lewis
Lewis is a male cyborg, a Literature specialist taken as a baby in Roman times. He is short but handsome, with a resemblance to the 1940s actor Leslie Howard, for whom he acts as a movie stand-in in the 20th century, along with stints as a double for Rudolph Valentino and others. Meeting Mendoza at a Company base in South America in the 17th century, he falls hopelessly in love with her. She is barely aware of this, of course, being already traumatized by the loss of her first love. She disappears from his view in the 19th century, and he tries to find her through the next 300 years, stumbling across Company secrets in the process. He is also the object of pursuit by strange pale little men, who were responsible for almost destroying him in medieval Ireland and would eventually manage to capture him. His memories of this have been suppressed by his superiors, to keep the existence of these strange beings a secret.
Kalugin and Nan d'Aragnée
Unusually, these two have been allowed to marry, and even occasionally work on the same projects together. Kalugin was recruited in medieval Russia, while Nan is from Africa, recruited in the same batch as Mendoza in the 16th century. She takes her name from Anansi, the Spider God of her people in Africa. She was orphaned when the Smoke Men, probably Arab slave traders, attacked her village.
Both Kalugin and Nan specialize in rescuing artworks. Kalugin gets the assignments where the art was lost at sea, in which case he is designated to be on board when the ship goes down, and stay with the artifacts till a Company sub picks them up. However it is soon apparent that Kalugin is lost somewhere on one of his operations. Which one it is, and why, becomes apparent in The Children of the Company.