Chronic dragons (Draco morbus), also known as disease dragons or plague dragons, are notorious for spreading terrible sicknesses. Thousands of sicknesses live in their bloodstream and scales and along with their allies the death dragons, they are probably responsible for the Black Death.
"Chronic dragons are the unholy offspring of Death and Pestilence... none who approach shall live." - Anonymous
It is unknown how exactly chronic dragons came into being but some suspect they originated during the Middle Ages. A very large and powerful chronic dragon could have started the Black Death in those times, wiping out up to half of early Europe's population.
They have no king and they are highly aggressive, territorial and solitary creatures. No two are exactly alike and all are powerful.
Most chronic dragons typically have dark scales and dull colors, but a few exotic species have bright markings across their bodies like that of a tree frog's. They also have an unusually thick and long tail, as well as enormous claws. Even one touch of their talons sends millions of infectious bacteria into the human bloodstream, making them one of the most fearsome and terrifying dragons.
A chronic dragon is difficult to approach, so little is known about their behavior. Even the air around them reeks with the foul stench of death and rot, not to mention the clouds of disease.