In the year 2039, the drastic effects of global warming have caused sea levels to rise, resulting in major loss of land. To ensure humanity learns its lesson, a fleet of powerful warships equipped with advanced weaponry emerges, causing overwhelming defeat for naval forces throughout the world. Calling themselves the Fleet of Fog, each ship has a "Mental Model," a humanoid avatar which represents the ship's heart, its "Union Core." Each model has a different personality but all follow an unknown authority known as the Admiralty Code, who have implemented a blockade to prevent humans from traveling across the sea. Seventeen years after the blockade, Gunzou Chihaya, a National Marine Academy alumnus, stumbles upon I-401 and its Mental Model, Iona, who sides with mankind for unknown reasons. Utilizing this newfound hope of achieving peace for humanity, Gunzou and his friends form a group of privateers, known as the Blue Steel, as they set out on a dangerous journey. [Written by MAL Rewrite]
Iona, I-401's Mental Model, is a calm, helpful friend to Gunzou, blending seamlessly with humans while secretly wielding immense power.
Portrayed by Fuchigami Mai
Former marine academy student, Gunzou captains the defected I-401 submarine, leading the Blue Steel Crew.
Portrayed by Okitsu Kazuyuki
opiumdaze★★★★★EP 11woah i didnt know kongo could do that !! iona's loyalty to gunzou is honestly admirable. no matter what happens, she always chooses to stand by his side and i really like how their bond has developed over the course of the series. i dont see them as anything romantic though. im also so glad takao is still alive !!! i was genuinely worried they were going to write her off lol
egerod★★★★☆Anime
