What happened, watch the show. However, she is a true friend to those around her. Yui has a lot of insecurities. Not all that jittery either. Good use of colors and a fully realized world.
Character designs are fitting and well done.
Their clothes are from simple to extravagant. With a fairly good amount of detail to them. This is really the only problem point. I have talked to many fans of this series and most of them as well as I say that this anime is excellent for suspense but to much of it happens off screen. However each battle serves a purpose to further the story.