Despite the resemblance, this image isn't fanart of FGO, it's a promotional image for an original asmr work with an original setting. It's getting more common for those "original" characters to resemble popular fictional characters. This is the link to the specific asmr work in question: https://www.dlsite.com/maniax/announce/=/product_id/RJ01301039.html/?locale=en_US