Korovyat's Sanctum

I had my fastest route to Masters with this deck (70% 14-6 win rate on the last leg of the climb - with the caveat of the obvious confirmation bias of the lottery-winner decks that tend to get posted here with barely-repeatable win rates).

I guess like most Korovyat Palace-Svetya's Sanctum decks it probably isn't much fun to play against if your opponent can't push through early.

The deck gets run over easily from power screw, but handles flood much better, so I gradually cut cards to make room for extra power (even if it looks like too much at first glance).

Skycrag Scalebreaker is such a great card, I don't know why she doesn't get played more - I guess the deck's win rate will go down if people are prepared for Torgov, Icecap Trader, Jotun Feast-Caller and Rost, the Walking Glacier to suddenly start flying at them (often with extra buffs courtesy of Korovyat Palace).
The two halves of the card give flexibility, depending on what is most needed in a particular match-up or board state and, if either or both aren't useful, the halves can be turned in to card advantage by using them as chaff for Winchest Merchant or Torgov, Icecap Trader to upgrade them to full cards.

And don't forget that Ice Bolts are also useful for saving your Rost, the Walking Glaciers from being transformed/silenced.