Diantha, Alain and others in “The Fiery Road to Mastership!”

If Iris is a Dragon-type trainer, then why...

Alain

[as if reading Diantha's mind] ...did she bring out Excadrill? [Diantha nods in agreement]

I've heard a rumour that she actually trained with Cynthia at one point.

Alain

Which means they each know the cards the other is holding.

It could very well be changing of the guard. This should be interesting.