Your opponent in this fight has a really strong Praxis Midrange deck.
Heart of the Vault can be really scary at times. Our strategy to combat his late game strength is to go wide, aggro as hard as we can and tempo to victory. We can usually break through his early units pretty easily, but it is important to combo your token attacks with
Rally,
Talir's Choice, and/or
Unlock Potential, and
Praxis Displacer to make room for your tokens. If you have
Arcanum Monitor, he fits nicely in this deck (replace 1-2
Humbug Swarm and 1-2
Talir's Choice) and is cheaper to craft than any rare. Have fun!
My campaign decks are all designed to be cheap and easy for new players. Check them out!