sigetch, hikonyan, nakano azusa, k-on!, frilled swimsuit, bad id, bad pixiv id, 1girl, :o, armor, bare shoulders, black hair, blue background, blush, body blush, breasts, brown eyes, casual one-piece swimsuit, cosplay, cowboy shot, fake horns, female focus, frills, hair between eyes, halterneck, head tilt, helmet, hikonyan (cosplay), holding, holding own hair, horned helmet, horns, japanese armor, kabuto (helmet), long hair, looking at viewer, low twintails, one-piece swimsuit, open mouth, pink one-piece swimsuit, simple background, small breasts, solo, standing, swimsuit, twintails