@Wolfwhistler,
@thegentelman
Her memory, like all memories, has probably skewed over time and over embellished the hero's looks.
To add, I'll use a single word: Doppelganger.
@omnixd
Here's why that will never happen.
1, Netorare, should you have completely forgotten the definition (which it seems you have), is to incite feelings of disgust or jealousy; usually on the behalf of the male protagonist. As she is in love with a faceless memory and not the protagonist, you cannot get those feelings. So, at most, it would be considered [cheating], which is really pushing it, or [rape].
2, the plot centers solely around the protagonist, the hero's blade, and those panties. It will never not be about that in till the end, or close to it. To end that plotline would end the series. Do you really want to see the series end of a stupid note like that? If so, literally stop reading, write your ending in a word document and leave it like that.
Cause you're not getting what you wanted.