1boy, 1girl, armlet, back, black_shirt, blazpu, blonde_hair, blue_eyes, blush, bracelet, breasts, bridal_gauntlets, brother_and_sister, castor_(fate), collar, diadem, fate/grand_order, fate_(series), halterneck, jewelry, looking_at_viewer, looking_back, medium_breasts, medium_hair, metal_collar, moon, pollux_(fate), robe, shirt, short_hair, siblings, thighs, twins, white_robe