Millie is a short imp with a long, devilish tail. She has red skin with white markings on her forearms and tail, eyes with yellow sclerae and black pupils, and long thick eyelashes that extend beyond the sides of her hair. She also wore shimmery, dark red eyeshadow, thick eyeliner and mascara, as well as black lipstick. Similar to her mother, she has two black horns with three thin white stripes and dark gray hair worn in a messy bob style with bangs that cover half of her right horn.