Rose of Perseus
The Word is the innate ability needed to interface with an ARC and operate an Ascendant. The ability seems to manifest in about one percent of children, initially appearing around the age of 11 or 12.
Once the Word manifests in a child, they become a Prophet Candidate, and generally begin training to become a Prophet and pilot an Ascendant. Usually they will become a Prophet with their own Ascendant shortly after they turn sixteen.
The Word itself first displays as a series of acute-onset dissociative episodes. Children often describe contact with one of ten different higher intelligences, which scholars call the Sephirot. The Sephirot grants instinctual knowledge of the ARCs, as well as the psychological ability to merge with an ARC.