The Evil Children are monsters from "The Cabin in the Woods" novelization exclusive. They are described as a group of 19 demonic children. They look like normal children but they have demonic traits.they are 6 black kids and 13 white kids some are boys and other are girls. They were mentioned in the elevator scene
There is no known image available for them.
They are a direct reference to the movie "Children of the Corn", based of Stephen King's novel of the same name.