I'd imagine concrete proof is pretty persuasive.

[Not for him. But again, he already believes slightly more in the godhood of Nico's, uh, dad. So sure.]

Believe me, the Sixth has honed the art of keeping to ourselves to the finest point imaginable. We're beautifully uninvolved, most of the time.

[And yet. More stories for another time. He shakes his head,] The door won't kill us; they'd have hid it better if they really wanted it to keep people out forever.