sei (bigaa), agnes tachyon (umamusume), umamusume, commentary, highres, 1girl, ahoge, animal ears, artist name, bag, black hoodie, blue jacket, brown hair, chemical structure, closed mouth, dated, down jacket, drawstring, ear ornament, earrings, grey background, grey pants, hair between eyes, hood, hood down, hoodie, horse ears, horse girl, horse tail, huge ahoge, jacket, jewelry, long sleeves, pants, red eyes, short hair, shoulder bag, simple background, single earring, smile, solo, tail