While watching F.Y with a friend, it came to our attention that Yui may not even be Seiryuu No Miko. Here's why we thought so (and this is going to be sort of short, but it may make you think):
* Miaka saw Suzako in the library before they were pulled into the book. Yui didn't see Seiryuu until she actually called him.
* Nakago convinced Yui to be Seiryuu no Miko, although she wasn't the real one. She only needed to be from another world (and a virgin) to call Seiryuu. She didn't need to possess any sort of special powers.
* Nakago played Miaka and Yui against each other the whole time so that they would be enemies, like Suzako no Miko and Seiryuu no Miko were supposed to be.
* Yui only agreed to become Seiryuu No Miko to seek revenge on Miaka and steal Tamahome from her.
So, what do you think of that? Chances are, Yui really isn't supposed to be Seiryuu No Miko, but Nakago uses her in hopes of gaining immortality! Oh, well. This doesn't take away from the greatness of Yui-chan or the major role she plays, however. Don't get me wrong. Well, thanks for listening to my rambling. Go and enjoy the rest of this site now. ^^