The Void seemed to have began around the time when Konoe was born.
A young female cat who went to the forest to gather herbs was the first one to notice the Void. When she returned to the village, Karou, her hand was stained a deep red. She cried as she told everyone that she didn't pick the herbs, she didn't touch them, and something like a knife cut her fingers. No one knew what she meant, and thought she was talking about a plant called 'blade grass'. Blade grass is a long thin leaves that could cut your fingers. Since they thought she accidentally picked blade grass no one took her seriously.
Eventually the other cats of started experiencing the same thing as that one female cat. Soon every living thing in the forest became dangerous to touch. It seemed like the plants, birds, bugs and butterflies couldn't be touched because they rejected the cats. Cats were rejected by the earth. However, this did not happen all at once. The Void had slowly crept from the edges to the center of Sisa.
The Void effects the forests in Sisa, after being infected the forests will "reject" the Ribika. The rejection usually leaves a cut where they tried to touch something infected with The Void. If a cat goes too far into The Void they will die.