Iona is the mental model (humanoid avatar) of the submarine I-401 from the anime series Aoki Hagane no Arpeggio: Ars Nova. As the main female protagonist, she partners with Gunzō Chihaya and his crew, aiding them with her advanced capabilities and unique perspective as an artificial intelligence. Iona is known for her calm demeanor, unwavering loyalty, and curiosity about human emotions, and her evolving sense of self and purpose shapes much of the series' narrative.