She is a Fog battle ship who takes the form of a teenage girl wearing a heavy coat that covers all of her body up to the nose, as her name suggested she is an anthropomorphic avatar of the fourth Kongou Class Battlecruiser. After a failed effort to defeat I-401, she befriends Makie and agrees to protect her, even if this means going against the Fog. Makie often calls her "Haru-Haru." (Source: Wikipedia)