Yea I understand but it helps if you don't end up getting Knight of Unaxio it gives you another aspect to make the deck a little stronger Plus Irina with backstab is a deadly combo. In your case Id...

Here is a similar deck I use sometimes, it is fun to play with but Knight of Unaxio is very inconsistent and its hard to be competitive with a deck based around that card. I think using Irina with...

To beat Serena and other weapon based decks why not add a few Stop thief? Or maybe swaping the layarian diplomat for some galderi, even if you don't use his ability he is still a 4/4 for 4 resources.