Mister Demi appears to be a timid and nervous man. Whenever he is shown, he has a paranoid demeanor. Despite this, he is kind and friendly towards his students. He likes peace, and still makes sure the students are following the rules. Mister Demi's white shoulder-length hair is accentuated by small black horns. Two pencils crown the top of his head along with black glasses. The left bang seems to resemble a keyboard. His white collared t-shirt has an eighth note in the center.