Michiko Hirai is a minor character in the live-action film adaptation of Thermae Romae, portrayed by actress Shungiku Uchida. In that version, she is depicted as a manga artist. In the broader Thermae Romae universe, a character named Michiko appears as the granddaughter of an elderly bathhouse owner whose establishment is visited by the protagonist Lucius Modestus. She is briefly shown helping her grandfather at the bathhouse before she departs, leaving the old man to mix up her name with that of another person. The information available about her background, personality, motivations, and overall development is extremely limited; she serves primarily as a fleeting background figure in the story rather than a fully fleshed-out character. Her role does not extend to having significant relationships, growth, or notable abilities within the narrative.