Kouwan Seiki, also known as the Harbor Princess, is a major antagonist in the anime series Kantai Collection. She is a formidable leader among the Abyssal Fleet, characterized by her commanding presence and strategic prowess. Her design features a harbor-like motif with maritime elements, symbolizing her control over the seas. As a powerful foe, she poses a significant threat to the Kanmusu, the fleet girls, and challenges their efforts to reclaim the oceans. Her role is pivotal in the unfolding conflict, driving much of the series' dramatic tension.