The Guild is an old and established group, whose history goes back beyond the Scream, when they were a dying breed due to the replacement of the Spike Drive, and they existed only on the fringe of space where Spike Drives were needed to set up Jump Gates. After the Scream (and the loss of all Navigators, but not their support staff and the means to create new ones) and the re-emergence of the Spike Drive, they have had a great renewal.
The Guilds base is made of various support staff, technicians, accountants and lab staff, although even this is a small number, probably less than 1000 across the sector. All of these people work in a undisclosed location, where they produce, train and support the best Navigators in the sector. Each Navigator is in fact 2 people, non-identical twins, the female of which is a powerful psychic and does the actual navigating, while the male is a security expert and assistant navigator. These Navigators are then Free Agents, who return a large part of their income to their guild and family. Older and more respected (female) Navigators are the unofficial leaders, but there is only one actual Navigator who is given the official position of Navigatrix (also female), and is in charge of the entire guild. This Navigatrix is chosen not based on age or experience, but instead based upon their sheer skill in navigation and psychic powers.
The current Navigatrix is a young women named Victoria Barker, who despite the early loss of her twin (William) and the transfer of her status to extended family, is considered to be one of the most powerful psychics in the last century, and is said to be able to pilot any ship across the sector in less than a day using something called "hidden paths" in drive space. These hidden paths are supposedly tunnels in space time in drive space, and are impossible for nearly everyone to find, let alone navigate through. She is far on the short side, very thin and generally tires easily when under physically exertion, all of which is apparently due to a chronic illness that has been with her since the accident that took her brother.
The Navigators themselves are a strange bunch, as they have been specifically bred for their task for nearly 1000 years. In reality they are less of a guild, and more of a very large family with some support staff. All Guild members are psychics for a start, sharing a constant telepathic bond with their other twin, as well as strong precognition and telekinesis powers. It is extremely rare to find a Bio-Psionic Guild member however, as if they do their jobs right they are never in danger. Physically they all share a few basic characteristics, but beyond this they vary exceptionally to keep the gene-pool healthy. Due to an extended time in their artificial womb and and a life lived in space ships, they are all unnaturally pale and slender, and their prerogative powers are so ingrained as to let them move an act with a fluidity of motion and reaction time that seems almost ethereal.
In the rare case when pair of twins are broken up (usually only due to the death of one of them) and if the other twin survives the deep despair it sends them into without committing suicide, they are considered "extended family" and are allowed to associate and breed outside of the guild, under the assumption that the guild will receive genetic samples of any of their children for free, as another way to refresh the gene-pool without weakening it.
Navigators are produced in a 3 step process, Conception, Alteration and Training.
First, one of the Gene-Masters will find a suitable genetic match between two pairs of twins, and genetic material from both will be combined to produce two more sets of twins. Despite the increased cost, these twins are gestated inside the same artificial womb, to promote psychic and emotional intimacy before they are even "born".
In this phase, which takes place from 2 months after conception to 3 years old, is when other genetic material and implanted knowledge is applied to the developing twins. Genetic donors from families with histories of psychics, long lives and freedom from disease or other defects can make a great deal of money by selling their genes to the guild for this step in the process. After this is complete, the twins are removed from the artificial womb and begin the third stage.
Here the twins begin a long course of intense training and preparation for their respective roles, all the while they are never separated to strengthen their bond. The final year of this training begins at age 18, and is the most intense, as for the first time in their lives the pairs are separated and have to lean to adapt to life on their own. It begins with less than a minute separate, but ends with a full month apart. After this the pairs are considered full Navigators of the guild, and are often leagues and leagues above regularly trained navigators.