And I got to 19/20. I came close to beating the dragon but I had 1 maybe 2 too many fire cards (fire immune).
Best advise it's a math game with your cards. Druid mage was beast mode. Paladine warrior (Captain America inspired. That's what I beat the your pic boss with Shield Toss -3 action pts). I took the non-bounty hunter rouge. Not sure if that was the best choice. Maybe Assassin rouge for the poison if I do it again.