akira hamaguchi, darling in the franxx, effects, liquid, 1girl, hiro (darling in the franxx), 1boy, zero two (darling in the franxx), pink hair, black hair, long hair, horns, swimsuit, topless male, closed eyes, sky, cloud, one-piece swimsuit, water, day, hetero, ponytail, couple, oni horns, partially submerged, blue sky, red horns, outdoors, hairband, open mouth