Hyuga is a mental model and former battleship of the Fleet of Fog in the anime series "Aoki Hagane no Arpeggio" (Arpeggio of Blue Steel). Initially an antagonist, she operates independently after being defeated by the protagonist, Iona. Hyuga is characterized by her intelligence, resourcefulness, and slightly eccentric personality. She later allies with Iona and the crew of the I-401 submarine, serving as a valuable strategist and engineer. Her role evolves from an adversary to a key ally, aiding in the battle against other Fleet of Fog vessels and contributing to the series' theme of understanding and cooperation.