robin (honkai: star rail), robin (summeretto) (honkai: star rail), sunday (honkai: star rail), honkai: star rail, honkai (series), absurdres, commentary, highres, 1boy, 1girl, bikini, blue hair, blue nails, bracelet, breasts, brother and sister, cleavage, cup, ddumo, drinking glass, facial mark, floating hair, hair ornament, halo, head wings, heart, heart facial mark, holding, holding cup, jewelry, large breasts, long hair, looking at viewer, multicolored nails, navel, one eye closed, open mouth, siblings, smile, starfish hair ornament, stomach, swimsuit, teeth, upper teeth only, very long hair, white bikini, wings, yellow nails