I'm guessing Semiramis; long black hair, earmuffs to cover her pointed ears while she's out in public.
I was waiting for someone else to say it. In the last post, I had a feeling it might have been her since she wears a neck ruff of sorts too, rather than it being hair like some assumed. I only refrained from saying anything because, well, she also wears long fingerless gloves and they were completely absent on her.
It would have been quite funny if it were Gilgamesh. He would see a kid who looks like he could be Gudao's. And then SAlter comes up running to get the kid, in matching clothes even.