Diagnosans are an alien race known for their natural ability to detect and treat a variety of diseases in all types of living things. Due to this, many of them become physicians. They have complex minds and an equally complex language, so much so that standard translator microbes cannot decode the intricacies of their speech. They are soft-spoken and gentle, further adding to their abilities as doctors. Diagnosans can diagnose disease in many different races, from humans to Leviathans, such as Moya.