I don't know if I'm an the average player or a horrible player, but my attempts at defeating Frostbranch in Austrilund were dismal failures. I once was in with two other players (one was Balance who was providing heals), and we still could not defeat him.
Who is Frostbranch? He is a giant ice based tree guy who has a death casting boar minion. He gets additional boar minions for each other player in your fight. These boar minions love to cast poison and vampires. He himself has a nasty cheat mechanic, and this cheat mechanic was destroying me. I would be able to down his minion (who had 1500 health), but by the time I finished with the minion, I would be down to a 1000 health or less, and I would barely put a dent into his 5500 health before he finished me off with either Raging Kraken, Icezilla, or Colossus. He also pumps out Blizzard and Ice Wyvern spells to soften you up.
Here's his mechanic. He has four phases. Phase one he casts out of turn at the beginning of the fight... everyone gets a double smoke screen cast on them, giving your next two casts a high chance of fizzling. If you manage to land an attack spell on your first cast, it will automatically clear the second smoke screen. He also starts with an extra power pip, and I think his minion starts with an extra regular pip.The out of turn smoke screen casting is in addition to his regular cast turn. In the next phase, he takes two to four turns as normal, with no extra casts. During the second phase, if you land a single target damage spell on him, he will grant you a "badge of courage" which helps for the fourth phase. On the third phase he casts an earthquake that doesn't use up his pips, although he doesn't cast anything else on that turn. This of course will destroy all your charms and shields (and traps on you). The badge of courage will not be removed (some reports say that it will eventually wear off, so you will have to keep attacking him in second phase to make sure you have it up). On fourth phase, if anyone does not have a badge of courage on them, he casts a genie that will hit those without the badge (lots of damage, and gives a debuff that hurts your next damage spell cast). the genie happens out of turn, and he still gets a normal casting for this turn. Very often, he will have enough pips to hit you with a good damage spell which you likely won't have a shield for, since he earthquaked you the turn before.
I spent more than a couple of hours attacking him over and over. Eventually, I did beat him. And this is how! First, I'm fire. I'm sorry, but this helped tremendously because of him being weak to fire. Secondly? Lucky. I got just enough shields and wand blasts past the smoke screen, as well as a very opportune Heck Hound. I used a deck that was loaded with seven glacial shields, a couple of hellephants and link spells (two pip casts to help get a badge and squeeze a tiny bit of life back), a couple of fairies (I don't have any secondary school). And one Heck Hound. For treasure cards, tough hellephants.
If I had no shield up, I would drop a shield. It was that simple. As well, I worked to take out the minion as fast as I could. Do not underestimate the minion! If my fight started with too many fizzles, the minion easily dealt 1500 damage to me by himself. The problem of putting in death shields as treasure cards is that they are only useful for the first couple of turns in the fight. The rest of it will be trying to keep up your health with shields and heals while trying to build up enough power with big hits on Frostbranch. With the constant earthquakes, you have to carefully time any blades you put on yourself so that you can do your next big hit the turn after. Putting shields back up can be hard because of the smoke screen fizzles. You may find that you went through a complete cycle of phases between earthquakes and not have done anything to Frostbranch. You cannot go all out on him, because he does too much damage before you can return with a big hit combo. So for me, I just kept my shields up, ate through his tower shields with my link damage over time spells, healed when I had two normal pips up, and dropped my treasure card Hellephants when I felt I still had a turn before earthquake. Here's the lucky part. I had seven power pips, a Heck Hound in my hand, and he didn't have Tower Shield up. It helped that I was going first in the turn, and it also helped that I got a critical. I then just kept dropping shields for the remainder of my turns until he died.
I was too exhausted to be excited :P