Machiko is a human student who serves as the class president in Gabriel White Tenma’s class at school. She has long black hair that is usually left loose and brown eyes, and she wears the standard school uniform. Since childhood, Machiko has consistently held the position of class representative, reflecting her responsible and earnest nature. In the manga’s later chapters, she is eventually elected student council president. Machiko’s personality is serious and diligent, exactly what one would expect from a class president. She is also notably patient, having grown accustomed to dealing with Gabriel’s incomplete or messy homework assignments. Her hobbies include solving crossword puzzles, and she is proficient at mental arithmetic. She is a member of the cooking club and also serves as its president. Every day, she faithfully performs step‑aerobics exercises as part of her routine. Despite the frequent conversations between Gabriel, Vignette, and others that involve angels, demons, or the supernatural, Machiko never suspects their true identities and cheerfully participates with ordinary, grounded retorts. Her role in the story is primarily that of a supporting character who represents the diligent and orderly human perspective in contrast to the chaotic and lazy habits of the main cast. Her key relationships are mostly defined by her duties as class president, particularly with Gabriel, whom she must regularly remind about homework. Machiko’s development centers on her gradual rise from class representative to student council president, while her steadfast sense of responsibility remains consistent throughout the series. Her notable abilities include her mental arithmetic skills, her crossword expertise, her dedication to daily exercise, and her competence in cooking club activities.