yui (niikyouzou), kal'tsit (arknights), arknights, official art, third-party source, 1girl, animal ear fluff, animal ears, bare shoulders, black boots, boots, brown boots, cat ears, cat girl, choker, closed mouth, coat, collar, dress, full body, green dress, green eyes, high heel boots, high heels, lab coat, long sleeves, looking at viewer, material growth, off-shoulder dress, off shoulder, oripathy lesion (arknights), see-through clothes, short hair, solo, standing, stethoscope, syringe, tachi-e, transparent background, white coat, white hair