serino itsuki, frederica (z/x), z/x, official art, 1girl, armpits, battleship, beamed eighth notes, blue eyes, blue hair, blue sky, breasts, cleavage, cloud, cloudy sky, colored inner hair, copyright notice, eighth note, firing, hat, large breasts, medium hair, mermaid, military vehicle, monster girl, multicolored hair, musical note, navel, open mouth, outdoors, pink hair, quarter note, ship, shirt, sky, solo, splashing, teeth, underboob, upper teeth only, warship, watercraft, white hat, white shirt