Medea Lily, from Fate Grand order.
Notable tags: purple hair, long hair, high ponytail, purple eyes, pointy ears, purple dress, mismatched gloves, mismatched legwear, thighhighs, boots, capelet,
This is just my personal opinion but this came out atonishly well, with enough detail on the prompt you can get pretty much a 1:1 with her official costume, and this costume is a nightmare.
Image 3 and 4 are just the "basic" tags I just told you, while first and second Images I gone full autism with the prompt. For a super accurate costume I recomend the latter, but just with those works well enough.
super accurate costume; asymmetrical gloves, mismatched gloves, solo, pointy ears, thigh boots, long hair, mismatched footwear, gloves, asymmetrical footwear, asymmetrical legwear, mismatched legwear, thighhighs, purple eyes, strapless, ponytail, scrunchie, boots, uneven gloves, purple gloves, strapless dress, dress, green gloves, very long hair, holding, hair scrunchie, breasts, purple scrunchie, collarbone, choker, purple hair, bare shoulders, purple footwear, purple hair, cleavage, capelet, see-through, high ponytail, high heels, blue footwear, purple dress, zettai ryouiki
No need to mention, you can do whatever other thing you want with it as well.
ILLUSTRIOUS ver
Lot more simple: pointy ears, purple eyes, purple hair, long hair, ponytail, sidelocks, scrunchie, short dress, jewelry, capelet, see-through capelet, asymmetrical gloves, asymmetrical legwear, pelvic curtain