Hearthpwn

UPDATE: I changed out a few cards here.  Note, sideshow spelleater won't copy Chromaggus hero power. O well, I was hoping to use it against him too.  Sorry no inclusion for you spelleater.

Mulligan for Freezing Trap, Explosive Trap, Deadly Shot, and Hunter's Mark.   You also want to ideally get a Misdirection on the board by the mid-game as it helps keep his board clear.

The name of the game is controlling the board.  Dump Chromaggus' 3 cost spells when you can, and slowly building up a board presence while removing his.   The key ones to get rid of can vary a bit depending on what he's played.  Early game, get rid of blue, red, and bronze.  Mid to late get rid of black and green to finish up.  If you're low on health of course dump red whenever you can, but taking a bit of extra damage a turn can help get the molten giants out sooner.

The giants, Sylvanis, and Thaurassian will be doing most of the damage here. I could maybe see an include of KT being good(well in pretty much any deck for this encounter), but I managed without it.  

Some may be wondering about the inclusion of the bow.  With it's 5 attack and immune ability, it was really useful for clearing threats without taking damage in the late game. Emperor is here to reduce the costs of his spells if things get a bit too hectic.

 I tried this match a bunch of times with druid, rogue, and mage.  For some reason control hunter did it for me. Oddly enough this deck also worked on Heroic Lord Victor Nerfarius.  But it was really close, I would maybe recommend dropping the Mountain Giants and Twilight Drake if you want to tailor this build for the Heroic Lord Victor Nerfarius fight.

 New additions:

Refreshment Vendor Helps keep you alive and trades well with some of his minions.

King's Elekk Helps with card draw and contests the board for the early game.

Quick Shot This gives a bit of card draw late game and can help give you the extra damage needed to remove something from the board.  

Things that could possibly be swapped out:

Webspinner I mainly like them in the deck because they are good in combination with explosive and misdirection. 

Animal Companion This card could maybe be changed out for more reliable removal,a nice taunt minion, or some maybe a good mid-game threat.

I thought about adding Bear Trap, but then I thought, "I'd rather prevent damage first with taunts or spells then take it just to get a taunt out". So idk it could work but I'm not convinced there.  Hope this helps someone.   Good Adventuring to ya.