Hi. Just a quick question. At the beginning of my turn I chose an opponents unit. He then pays me 2 resources. GREAT! But don't they go back to the pile before I can use them? I mean, it's the beginning of my turn and then right after I have to reset my resources and take what my kingdom gives, right?

During the same Action Window in the Beginning of Turn phase during which you're using Illyriel's Action, you could also spend those two resources on playing a tactic or paying for a card effect. After the Beginning of Turn phase comes the Kingdom phase where, yes, you'll lose them if you didn't spend them.

Even if you don't have a use for the resources, your opponent didn't get to use them for anything constructive either. Denying them to your opponent is more the point of the card than gaining a benefit from them yourself. Also, you can target one of your own units with a powerful "enter play" effect and return it to your hand.

What a good point. Thanks