Myrthryl is a 300-year-old demon. She has shoulder-length pink hair, purple eyes, elf-like ears, and black demon horns on her head. She's slim, standing 175 cm tall. She wears formal attire consisting of a black jacket with golden ornaments, a black vest with golden buttons, a white long-sleeved shirt, black gloves, black pants, and black knee-high boots with gold rivets. Myrthryl is cold, calculating, calm, and confident. Myrthryl prefers not to act on emotions. She is an expert duelist.