When Yui sleeps, Kanato lays his head on her chest and listens to the beating of her heart.
In a strange way, it reminds him of being a child again, of those times when Mother would hold him in her arms as he drifted off to sleep, his throat sore from singing to her. He thinks this must have happened more than once, even if the memory feels about as real as a dream now.
Sometimes he looks up and sees a strange smile on Yui's face, a smile that doesn't belong. She smiles so rarely, anyway, and when she does it is a soft, tender little thing, delicate as a butterfly's wing. He thinks if he ever saw her smile like that at anyone but him he would kill them on the spot.
But Yui's sleeping smile is not like that at all. It is wide, contended, almost smug. As though she's plotting something in her dreams.
And why does her heart do that, anyway, suddenly beat harder, like it's trying to escape the confines of Yui's chest? Kanato knows more about dying human bodies than warm, living ones, but that doesn't seem right to him.
"Stop it!" He snarls, and the strange smile vanishes abruptly. She is Yui again, soft and sad and kind-hearted.
For a while, Kanato watches the slow rise and fall of her chest, watches her tender mouth and pale eyelids. He doesn't know what he's watching for, exactly, but it makes him feel better to watch.
When an hour passes without incident, Kanato slowly lays down his head again, slipping his cold hand into her warm one. After a moment's thought, he pulls her hand close and kisses it.
She is the picture of innocence, everything he is not. He wants to corrupt her, wants to stain every part of her... but he also wants that tender smile. He frowns, wondering if he can have both.
"Sleep well, Yui-san," he murmurs, listening to her heart beat. "I really like you, you know. Stay with me forever, won't you? Don't leave me... like she did."