The Plague of Ancients was a widespread disease that is said to have wiped out almost all humanoid life in Altheria, notably the highly-advanced Dyrennians. It was also around this time that the modern date system was created.

The disease was said to have been spread through infected water, with some theorising that the early Daemons cursed the only other existing race, using ancient Daemonic magic to infect the water supply.