I have tried countless times to beat this mode, I just can’t. I feel like I would have to resort to the 0 mana sound the bells Paladin strat but I know that’s not a thing anymore. I’m not sure how to go forward.
So what worked for me was getting captured flag (+1/+1) as well as recurring villain (resummons if attack is increased) which makes it resummon itself every time it dies.
I took the cost reduction choice in the tavern every time it came up and I got suuper lucky with a zero mana rafaam which I managed to draw early in the last fight. I played as the warlock for card draw which is very helpful as long as your health doesn’t get too low.
Another really good combo is taking elixir of vile (spells cost health instead of mana) and then drafting witches brew (2 mana heal 4 health, echo, shaman spell) this lets you heal to full and cast whatever you like once you draw it. I took the shaman minion that gives you unlimited spells per turn as long as you cast them all and this lets you cast a whole bunch of spells early in the game as long as you have the health to support it.
I’ve also found that the passive that gives draw three cards is actually really good. Originally I was playing it with the idea that I should draft only cheap cards so I would burn less, but I think that’s kind of the wrong way to do it. Instead you should use it to cycle through your deck quickly so you can grab your overpowered treasure cards and play them early enough in the match to get a huge lead.
I had good success combining it with Togwaggle’s Dice (randomizes the cost of cards in your hand every turn) because the dice get better with your hand size. The more cards in your hand the more likely you’ll roll into a huge discount on something crazy and really strong and Togwaggle’s dice also likes to give you one and zero cost cards from time to time meaning that with ten cards in hand you’ll be very likely to get enough of a discount that you can play three per turn and not burn your deck too badly.
Also Elixir of Vim and Elixir of Vigor are obviously made to be used together, but I’ve never gotten that particular combo offered to me.