Persephone watches both of them, a little apart from the conversation. She's vaguely worried about Thanatos, in a way that she wonders a lot about his life before now and if he has any time to himself and also maybe what his whole entire world was like because it's slightly concerning? But this--she has no base on.

So she doesn't have anything to base what he says on, grasping for straws to connect it to something. She just has more backstory to connect with.

"You mean in general, why it chooses one world over another, or is this more about your role at home? I'm sure they wouldn't doom your world."