1girl, ass, black_panties, black_thighhighs, from_behind, greyscale, hat, kono_subarashii_sekai_ni_shukufuku_wo!, lace-trimmed_legwear, lace_trim, long_hair, looking_back, ltstry, megumin, monochrome, mountain, outdoors, panties, solo, thighhighs, top-down_bottom-up, underwear, witch_hat