He is a blue colored version of Eraser, hence his name.
Green Eraser, along with Green Pen, appeared in Episode 17 The Reveal. He and Green Pen were both recommended by englishcreamcakes, who happened to be mentioned as the first Pencil voter in the same episode.
Orange Eraser appeared in episode 18. He is an orange version of Eraser. He was recommended by metroidshroom.
White Eraser was one of the gaspers in episode 20. He was recommended by razeblox. He is a white-colored version of Eraser.