"You're welcome," Ardyn answers, being insufferably him through and through. Nevermind that he doesn't actually know what it means to be him most days anymore. Being who Gladio thinks he is tends to be easier anyway than any kind of vulnerability that might accompany being actually seen.

He's not too happy about his mind being forcibly cracked open and memories of his spilling out, but- He also can't change what happened now, can he? It also is giving him some interesting insight into Gladiolus himself, who... Well, put simply, Ardyn still isn't used to seeing many of Noctis' entourage as people in their own rights. They were moreso obstacles for him to overcome in getting to his true goal. He knows Gladio is a person, but it makes it easier sometimes to not perceive him as such.

"I had heard rumblings of your absence and something to do with Cor, but it didn't seem especially relevant so- No, actually, I didn't realize. I can believe he's stubborn enough down to his soul though to be still around." Despite everything, so many fragments of Ardyn's past remained stuck in their star like splinters under his skin. "That's why him and my brother got along so well, I'm sure."

And if that piece of things - that the Founder King was family - wasn't something Gladio gleaned from the memories, Ardyn perhaps just gave away more than he meant to by assuming.