Hisuian Braviary appears to be based on the Steller’s sea-eagle, as evidenced by its larger size, dark plumage with white highlights, and pointed central tail feathers. It is described as visiting the Hisui region from the north in winter, just as the Steller’s sea-eagle migrates to spend the winter in Hokkaido, which the Hisui and Sinnoh regions are based on. Steller’s sea-eagle also has a rare dark morph that resembles Hisuian Braviary’s shiny form. Hisuian Braviary may also be based on the Papuan harpy eagle, as evidenced by its larger size, contrasting dark and white plumage, and distinctive feather crest on his head.