1girl absurdres animal_ear_fluff animal_ears arms_behind_back bangs bikini black_bikini black_hair blue_archive blush breasts cat_ears cleavage closed_mouth e_name frilled_bikini frills hair_ribbon halo highres long_hair looking_at_viewer navel off-shoulder_bikini off_shoulder official_alternate_costume red_eyes ribbon serika_(blue_archive) serika_(swimsuit)_(blue_archive) solo standing sweat swimsuit twintails