The Diagnosans are a sophisticated spacefaring humanoid race widely acknowledged as the natural physicians of the galaxy. Their most readily notable characteristics include a slim, two meters tall body; an enlarged head and long dexterous fingers which likely aid in surgery. An extremely acute sense of smell and natural ability to detect even the smallest pathogens has also granted them excellence in their profession. Ironically, the Diagnosans themselves are terribly vulnerable to airborne germs and must wear filtering air masks nearly all the time.
Diagnosans are a pacifist and gentle species which dedicate their efforts to detecting and treating illness in all sorts of oddball alien races. Their brains are exceptionally complex and so is their language, resulting in standard translator microbes having difficulty to decipher the nuances of their speech. When performing surgery, they will prefer to use a sterile force field to keep the area clean, allowing them to remove their mask apparatus for that time. If a patient cannot be saved, the Diagnosan will freeze the body just before death in order to preserve the organs for future patients.
It has been proposed that the nasal cavities of Diagnosans lack the protective hair and mucus present in Humans and other species, thus explaining both their greatly enhanced olfactory sense and their vulnerability to airborne pathogens.