Engineering Lt.j.g. Doyon hailed from Delta Four. His Deltan heritage gave him a superior spacial perception, a limited form of telepathy, pheromones, and autophobia. His sense of time and space made Doyon a natural shuttle pilot and helmsman. He chose engineering as his field, because he understood warp physics and transdimensional mathematics intuitively.

Deltan telempathy manifested as the ability to send/sense physical sensations, but not thoughts(words) or emotions. The sensations could be pleasurable or not. He could project a visual image into someone's mind, or he could experience the tastes and smells of a meal that another person had eaten. Deltans could use this ability to block sensations, such as pain, in another.

Doyon's pheromones caused him to be subliminally attractive to the females of most humanoid species. The phenomenon was involuntary, and often inconvenient. Pheromone production was increased whenever he encounted a new female. It was decreased if Doyon is ill or fatigued. Combined with their telempathy, Deltan sex was very intense, and involved the temporary mingling of selves. Non-Deltans often were unable to return to themselves after the experience. Early encounters resulted in psychoses for some, catatonia for others. Deltans in StarFleet were required to take an Oath of Celibacy, to protect their shipmates.

Autophobia is the fear of being alone. Deltans suffered psychological distress if forced to live for extended periods without social contact. Deltans serving together would commonly become roommates and bedmates.

Doyon was six feet tall with an athletic build. He was fair-skinned and dark-eyed. The Deltans'most distinguishing physical feature was the total lack of body hair. Torso, limbs and head were free of hair. Even eyebrows were missing.

Doyon had been the most social crewman on any starship that he had served aboard. His sense of humor and his loyalty made him popular with the crews, and not just the crewwomen. His professional performance made him popular with his superior officers as well.