Nachi is a Fleet of Fog vessel, the reincarnation of the World War II Myoukou-class heavy cruiser Nachi. As a Mental Model, she possesses a humanoid avatar that gives her a distinct identity and personality. She is notably respectful and soft-spoken, especially when addressing those of higher rank, and often displays an apologetic manner even when no fault exists. She is part of a quartet of sister ships: Myoukou, Ashigara, and Haguro, all of whom appear in the series. Nachi serves as a supporting character in the films Ars Nova DC and Ars Nova Cadenza, contributing to the broader conflict between the Fleet of Fog and humanity. Her motivations are not extensively detailed in the available material, and her character follows a limited arc within the films. As a heavy cruiser, she is armed with the same advanced weaponry and defensive capabilities that characterize the Fleet of Fog, including formidable energy-based cannons and a durable protective barrier. Her primary relationships are with her sister vessels, particularly the more energetic Ashigara, who often influences her actions. Her specific role in the larger narrative and any notable development are not elaborated upon in the accessible sources.