[Does Ardyn actually care that the world around him is rotting, as surely as if infected with Starscourge? Not a bit. If anything, it provides him with a sinister satisfaction that he can ruin life for Noctis here as well as he can within Eos. As foul as the stench of festering decay in the air happens to prove, it's oddly satisfying to see the demarcation of where his influence ends and the prince's begins. He's no king yet.

Ardyn tsks at Noctis with a disapproving lift of his eyebrow and shake of his finger.]

Has the royal line faltered so far over the years that even basic courtesy is too impossible a challenge? Why even your father gave me a warmer welcome when I met him bringing terms of peace.

[A false peace. A complete sham. Ah well. At least it was executed well enough.

But what does he want? To torment Noctis to the brink of breaking, to force him to the edge, make impossible heartbreaking choices before he dies. He wants this would-be King of Light to suffer and agonize, in full knowledge that it will distress the Astrals and the Crystal. Punishment fitting for their rejection, their duplicity. To experience the fear of failure before he is snuffed out.

Ardyn spins on his heel and flings his arms up into the air with grandiose gestures.]

But since you asked, what I want is for our fledgling king to go back into his Crystal and stay there until he's fit to emerge.
[He turns back around and while the words are flip, the intention is not.] I've waited this long, what's a few more years, hmm?