Iona

Iona is the Mental Model of submarine I-401, taking the form of a mysterious young girl. Acting upon an unexplained directive, she sought out Gunzou Chihaya as her captain and pledged absolute loyalty to him. In her earliest days, her conduct was purely algorithmic—cold, calculated, and devoid of warmth. Yet through countless battles alongside Gunzou and their human companions, something profound began to stir within her: an independent sense of self gradually emerged, and genuine emotions quietly bloomed beneath her stoic exterior. Today, she stands as the irreplaceable heart and soul of the Blue Steel Fleet.