Iceheart

The object of the game is to one-shot your opponent. The first time I demo'd this on Overmaster, I think he went to -53 in one hit.

You cannot include any spells in the deck except 2-3 Aid of the Hooru or, if you prefer, The Witching Hour / Decimate / etc. I would recommend Aid of the Hooru purely because its value does not decrease as the game progresses (TWH) and has the highest set cost in the game. DO NOT change the power base if you use Witching Hour, you never want to cast it, only include it.

In a deck with only one spell, that spell is a guaranteed draw by Jarrall Iceheart when he connects with your opponent. If you equip an Overwhelm weapon on Jarrall prior to attacking, two things happen:
1) You are more likely to get damage through to your opponent, which will activate his ult.
2) Suddenly, all of the damage he deals is Overwhelm.

E.g. If your opponent has 5 grenadin on the board and you connect with an Overwhelm Jarrall, all of the extra damage goes through and your opponent gets hit for (12-1)*5 = 55 in a single shot.

You only need 2-3 of whichever spell you choose, because you actually want low odds of drawing the card--you need it in the deck when he activates, and you are banking everything on winning in 1-2 hits. Save your Spellshield Architects to protect Jarrall.

On the sideboard, Soulfire Drake is risky because of the high influence cost, but does increase the odds of getting damage through for sweep; you'll still need an Overwhelm weapon on a Flying, Charge Jarrall if you want a one-hit kill.

Tailor deck and sideboard to meta, keeping in mind how the deck operates.