Board Thread:General Discussion/@comment-173.69.148.56-20140221235829/@comment-27.111.71.74-20141009022553

Being a major Sachi fan, I think Yui may have modeled her appearance after Sachi after seeing the psychological impact she had on Kirito.

So, before she came out into the Aincrad world to meet Kirito and Asuna, Yui had no real appearance or form. So, after witnessing the death of the sweet young girl whom had such an impact on Kirito, she modeled her appearance after her, perhaps to catch Kirito's eye, I don't know. It works in my mind.