She has no wings how is she Remilia.
And dont begin with its the time before she became a vampire!
She's more like Yuuka.

Looks like Yukari's parasol and dress to me, but the Pixiv page doesn't seem to have character tags via my Google-fu.

I don't even think it's tagged with Touhou or any character from said series.

As previous comments said, there are no Remilia/Touhou tags on pixiv.