Secret
Zexion has probably told Demyx to stop making his eccentric collection of sounds hundreds of times
"They are annoying," he says, but it's a secret that he somehow developed a fondness towards them.
The squawks during an ungainly fall, or a little squeak when Demyx was found where he wasn't where he was supposed to be had nearly become… endearing.
But what now?
Feelings were not something he excelled in expressing even in his past life, and particularly not now, when he didn't even have a heart to feel them with. Perhaps… it was better to let things stay the same and not let them get out of hand. Yes, that was what he would do.
After all, who knew what Demyx would do next?