Varden Dawngrasp mercenaries

Hello everyone I have never been a huge blizzard fan until Overwatch and I think i have gone into a forum once during the Sombra ARG. But today I am frustrated enough to make my second to complain about the 7th fight in Dawngrasp’s story. What are these cards and this ridiculous rng! Before making this post I got all the way to the last turn and was able to turn the outrageous 12/12 Dragon into a 1/1 sheep only to have myself beaten by a fire card with the exact amount to defeat me after being hit by all of the minions. Is there any strategy to it or pulls I should look for to get me through this finally before I go insane?

There are some guides at Hearthstone Top Decks.