He's not so much pissed off as protective. He knows there are people out there who think Anna could be do better, she's a Princess, the heir to her sister's throne for now, and he's just. Just a simple ice harvester, raised by trolls in the wilderness, and giving him titles doesn't really change that. He knows how out of his league she is, and he knows that means he just has so much more to prove, to make sure he's worth her. And rumours like Dave's joke could cause issues, at least as far as he sees it.

"District... 9?" He thinks that's the one he found her in, but in truth he had been more focused on finding familiar faces than recalling details like that. But Dave gives more of a time frame than Elsa's vague 'months' and in truth it... sickens him. How they have such abilities like this... he's never wanted Grand Pabby more, Kristoff is sure he'd have some knowledge on how to fix this.

Brow still furrowed he looks up, studies Dave before speaking. "And you've been... looking after them? After Anna?"