Brutal for you, but if you play it right Brutal for your competitor. I have been playing since season 3, casual player who gets bored easy, then messes with decks and hits legend mid to late most months
I was playing Quest Warlock with Gnolls and Giants and got to Rank 3 but it was not cutting past the Mages and Shamans. It was not fast enough so I looked at ways to speed it up Credit to ConCuThanKy#1292 who gave me the basis for this deck. Mine is just more Brutal!
Main Upgrades: Double Flame Imp for more damage, Bloodmage to extend damage and draw
Drops: One Armor Vendor (I am thinking of changing the other out for an Alter of Fire. One Manafeeder because I think the Bloodmage is better.
Mulligan for the Mithril Rod, unless you are against aggro. Look for early damage and draw. Mithril Rod coined out on 2 into Backfire on 3 is Brutal! Imps for damage, Imps for draw. Unstable Bolts for damage and early dangerous minions. Against aggro minion decks keep a Soul Rend and try and burn as many cards as you can, getting to zero cards is Brutally good!
You should aim to complete the quest ASAP between round 5 and 7, earlier is better. You need to know the decks that could Murloc your Prize, so plan your damage or play your prize before they get to round 7.
Early Tamsin with healing and the get her back with Raise Dead
Planning your Mithril Turns with Backfire and Hand of Guldan
Closing out the game with Tamsin into Double Guldan and a Backfire = 9 cards and three damage for 48 damage
No fear, go for damage, card draw, card burn and be Brutal!