[Name] Asmodeus [Source] Terranigma [Symptoms] 
Many ages before Ark's adventure to the surface of the world, the previous generations of Humanity were decimated by an airborne virus with an estimated mortality rate of 90%. The virus was named by Dr. Beruga who was able to synthesize a vaccine of 80% effectiveness for it. Asmodeus was later utilized as a bio-weapon to completely depopulate a city, save for one child survivor who was seemingly unaffected and hid underground.