yamanaka kotetsu, tiamat (fate), fate/grand order, fate (series), game cg, official art, third-party source, 1girl, aqua hair, bare legs, blue background, breasts, bright pupils, caustics, closed mouth, crossed bangs, dragon girl, dragon tail, feet out of frame, fingernails, hair between eyes, highleg, highleg one-piece swimsuit, horns, large breasts, light rays, long hair, long sidelocks, looking at viewer, one-piece swimsuit, pink eyes, plunging neckline, pointy ears, sharp fingernails, sidelocks, smile, solo, sunbeam, sunlight, swimsuit, tail, tiamat (swimsuit archer) (third ascension) (fate), underwater shot, upside-down, white one-piece swimsuit, white pupils