Haruna  

Haru-Haru, ハルナ

The girl you're referring to is an anthropomorphic representation of a Kongou Class Battlecruiser named Haru-Haru. She wears a heavy coat that covers her entire body except for her nose, and she takes on the form of a teenage girl. Initially, Haru-Haru tried to defeat I-401 but was unsuccessful. Afterward, she befriended Makie and agreed to protect her, despite going against the Fog's orders.