Blight Dust Beast
"The beast that was infected by the invader was a nascent soul stage beast, called as the Blight dust beast. It has the body of a butterfly, the tail of a bull, and the horns of an antelope. It has four wings that look like large leaves and has countless fine hairs on it.
It was found in the eastern part of the forest called as the gray muck swamp. It is located far beyond the eastern town, more than six hundred kilometers away. The swamp itself is quite small but the danger level there is quite high and seldom do people go there.
The plague occurred due to the ability of the Blight dust beast. Its ability allows it to release large amounts of invisible dust from its wings that is toxic. This dust can affect both plants and beasts. The creatures that die from this are then eaten by the beast.