Kama in her Second Ascension outfit from Fate/Grand Order. She is in her teenaged form here, with shoulder-length white hair and a pink bow tied on the left side of her head like Matou Sakura. She wears a purple halterneck top that becomes see-through around the abdomen, gold shoulder pads holding a series of purple strips, tight purple sleeves, a gold metallic bikini bottom, purple thighhighs, and gold high heels.
Note that her halterneck top is the same in her First Ascension. The best way to tell them apart is that the First Ascension outfit has the dark skirt beneath the top's sheer part, whereas the Second Ascension outfit has a gold metallic bikini bottom.
This tag implicates kama_(fate) (learn more).