I'd been tickled by this idea a little as Yuki slowly became more and more of a chess piece in her own life, and after seeing a panel in Chapter 33 where she refuses food this sort of took root in my mind.
Prologue
"But Yuuki,you haven't eaten anything yet!" Yori said, a slight frown touching her features.
"No, I don't feel like eating at all." Yuuki lied. Yori nodded with understanding, and Yuuki almost started at how easily the lie had been accepted. Yori was usually so perceptive... Worryingly so. The girl was going to find out about the supernatural side of life at Cross Academy fairly soon if Yuuki wasn't careful. Could it really be that this teensy white lie had gone down without comment? Why... Why had she even lied in the first place? Yuuki was a comfort eater - chocolate and ice cream were her favourite ways of cheering herself up. Stressed as she was at the moment, her stomach was all but verbally begging her to eat everything in sight.
The stress that was getting to her was the result of Kaname, of course. He had neatly dodged Yuuki's past yet again, and... For lack of a better word... Manipulated Yuuki into becoming his lover. Why did she need to prove her faith to him? What kind of game was this? If Kaname truly did love her, why was he being so mistrustful? The gaping hole in Yuuki's memory had never been so apparent or so irritating. It placed her out of the loop, and everyone around her seemed more powerful and privy to secrets deemed far to important for silly little Yuuki to be let in on. The entire situation was making Yuuki feel so helpless and out of control of her own life.
The anger that she inwardly felt towards those around her momentarily made her forget the innocent lie she had told as well as her hunger, and with a half-hearted excuse that she was going to visit her father because she felt off, Yuuki returned to her room. The feeling of satisfaction she had afterwards was difficult to place, until Yuuki realised that it was from finally controlling one tiny piece of her day, for the first time in what felt like forever. Sure, it was trivial, but it was an achievement of Yuuki's. Nobody had been there to make her eat, so Yuuki had chosen not to. A grin slowly spread itself across her face from the realisation.
It felt like a personal victory over every vampire at Cross Academy. An intoxicating one.
