1girl, arknights, armpits, arms_behind_head, arms_up, bikini, black_bikini, blue_sky, breasts, cloud, criss-cross_halter, day, demon_girl, demon_horns, hair_intakes, halterneck, horns, long_hair, natoriusu_sansei, navel, official_alternate_costume, outdoors, purple_eyes, red_hair, sky, solo, standing, stomach, surtr_(arknights), surtr_(colorful_wonderland)_(arknights), swimsuit, swimsuit_cover-up