Millie is a short red-skinned imp with a long tail, striped horns, and short messy black hair. She has yellow eyes, a small beauty mark, and a more human-like face with a tooth gap. She wears dark makeup and has a heart tattoo plus a few white spots on her body. Her outfit is mostly black, including a choker, crop-top, gloves, torn pants, and toeless footwear. -For sleepwear, she wears a black sleeveless nightgown with thin straps. Millie is a cheerful, energetic extrovert who speaks her mind and loves her job as a skilled, violent fighter. She can be ruthless and focused on completing missions, even showing little sympathy for targets. Despite this, she deeply loves and protects her husband and family. She has a playful, childlike side but can become dangerously aggressive when angered, sometimes losing control. She also feels underappreciated at times and wants to be seen as more than just a killer. Millie fights using a large battle axe. She also has a strong southern accent. Millie works for I.M.P [Immediate Murder Professionals] in the Pride Ring of Hell. I.M.P is a company that travels between Hell and Earth to kill humans who their clients hire them to kill. Her boss is the crude and loudmouthed Blitz, and she works alongside her husband Moxxie, and Blitz's lazy hellhound daughter, Loona.