The Viyrans were a race of mysterious beings, infamous for the creation of a variety of biological and viral weapons.
Biology
The appearance of the Viyrans is unknown, as they were always seen in white hazmat suits. They appeared to be humanoid, with three fingers and a thumb on each hand. They had no spoken language, but communicated telepathically, through hand motions or by trying to replicate an individual's voice. (BFA: Patient Zero)
Technology
The Vuyrans may have created the Amethyst Viral Containment Station to safely store the deadly viruses they created. They used flying glass coffins to collect infected patients to try to cure . They could time travel. (BFA: Patient Zero) They could modify the memories of others, as well as create perceptual barriers. (DWS: No One Died, BFA: Mission of the Viyrans)
Diseases
The Viyrans were best known for the diseases they created.
- One disease could destroy the minds of everyone on a planet. (DWS: No One Died)
- One disease was a metallic-looking worm which was six inches long. It could induce beneficial coincidences. It could transmit itself through telephones. (BFA: Urgent Calls)
- Another disease could cause a frenzy. (BFA: Urban Myths)
- Another disease could grant wishes. (BFA: The Vanity Box, BFA: The Wishing Beast)
- A fifth disease would warp the DNA of the host, slowly killing them. (BFA: Mission of the Viyrans)
History
The Viyrans originated in a place far distant from Mutter's Spiral, Earth's galaxy.
The Viyrans waged a war with an unknown force with a variety of viral weapons. Peace was eventually reached and the biological weapons were gathered together in Amethyst Viral Containment Station to destroy them. During an incident with the the Doctor and the Daleks, the viruses were spread throughout the universe. The Viyrans began travelling through the universe to find and cure these diseases. (BFA: Patient Zero)
In 1962, a viral particle fell onto Lower Downham. The Viyrans followed it to try to neutralise it. The virus was too dangerous, so the Viyrans evacuated the whole village and set up a perceptual barrier, making it seem to disappear. The Doctor and Rose interfered, but the Viyrans removed everyone. (DWS: No One Died)
In 1974, one of the Viyran viruses transmitted through telephone lines was found on Earth. It infected Lauren Hudson and caused her to have phenomenal luck. (BFA: Urgent Calls)