Hello! First of all, thanks for all views and likes in my deck!!
Second, this is an old deck (from before BRM).
I recommend you to see this one, if you're looking for my deck on season 13.
This is a adaption for the current meta of the deck I used for reaching legend rank in three days in season 11 in NA server.
I'm climbing ladder right now, and the atual list is probably the one that i'll use 'til legend, with some tech cards.
About the deck.. Basically, it's an anti-meta Priest.
You usually wins by overdrawing your opponent, since he will runs off steam faster than you.
It's a 'play to not lose' gameplay. Try to keep your opponents board always clean, and you probably will win. Play slowly, analyze the benefit for a more aggro approach on your moves, analyze the benefits for a control move, and then act.
Mulligan/How to play:
Mech Mages/Hunters Face -> Mulligan for Zombie Chow, Wild Pyromancer, Power Word: Shield, Northshire Cleric. Do not keep Auchenai or Injured Blademaster if you don't have Circle of Healing. Keep Sen'jin Shieldmasta if you have coin. Against Hunters Face, use the Explosive Traps in your favor to draw a lot with Circle of Healing, and be aware when you drop Auchenai, since you will not be able to use Holy Nova or heal yourself. Against Mech Mages, try to catch Mirrors Entity with Zombie Chow so you can kill right after healing yourself, and be aware of Antonidas (Mind Control it or kill with SW:Death). In those matchups I usually preffer using Circle of Healing with Auchenai instead of Blademaster, since my Auchenai dies easily and I can heal myself back, but it will depend on your board AND hand. Try to steal key minions with Cabal Shadow Priest, such as Mad Scientist and Mechwarper. They both are easy matchups, in general.
Druids, Paladins, Hunters Mid-range -> Mulligan for Injured Blademaster and Circle of Healing, Vol'jin, Sen'jin Shieldmasta, and the usual Power Word: Shield and Northshire Cleric. You should keep Wild Pyromancer against Paladins Muster of Battle (use with Holy Nova after Quartermaster). Against Druid, try to kill everything in board, Blademaster+Circle in turn 2/3 means winning. Ysera has a lot of value against Druid too. Just don't let him overflow the board and you're safe. Loatheb gives you a extra turn to heal as well. Against Paladin, destroy their minions with Wild Pyromancer, kill the big threats trading, don't put too many minions on board, steal Tirion, wins. Try to adquire the board before a Paladin drops Tirion, since most of them runs a Harrison too and will wait until you steal Tirion to use it, so even if he kills Tirion and use Harrison, his turn is over. Hunters Mid-range arent a big problem, just be aware of Savannah Highmane after turn 6, Unleash the Hounds and Freeze Traps. Basically wins the board, wins the game. Be aware of the new Feign Death Hunter. If he drops a Harvest Golem, you already now that he has it and probably will use in Savanah/Sylvana.
"Tempo" (Control) Mages -> Against the 'new' Mage that is very popular atm, you mulligan basically for Zombie Chow, Northshire Cleric, Wild Pyromancer, Power Word: Shield. Try to use cheap spells (PW:S, Naaru, Coin) to burn Counterspell and gain tempo. Try to activate Mirror's Entity with weak minions. It's not a hard matchup, but you'll need to draw and play correctly.
Warriors, Freeze Mage and Mirror Matchs -> Mulligan for Injured Blademaster and Circle of Healing, Power Word: Shield, Thoughtsteal and Northshire Cleric. You can keep Vol'jin if you want, because he can do a huge tempo gain. Draw as much as you can, so you can aswer Alexstrasza with 2x Light of the Naaru and Shadow Word: Death, which will give you a removal, 6 heal, and a 3/2+1/2 on the board. Try to trade with Dr. Boom, so you can keep your Mind Control for Grommash or top threats (Sneeds, Ysera, etc..) that will come later in game.
Against Freeze Mage, Loatheb is an amazing card, specially when the board is crowed with your minions, stopping a Flamestrike or Frostnova + Doomsayer, or with a Shadow Word: Death after Alexstrasza. Try to steal Acolyte of Pain with Cabal Shadow Priest so Warriors and Mages will have their games slowed a lot.
Rogues -> Mulligan for Zombie Chow, Sen'jin Shieldmasta, Wild Pyromancer, Northshire Cleric, Auchenai Soulpriest, Circle of Healing, Holy Nova, Loatheb. Rogues are a big problem for Priests, since they do a lot of damage too fast and we need time to heal, so try to burn their Sap with early minions. Never put a lot of minions on the board if the Rogue have high attack on his weapon and havent used Bladeflurry yet. Try to play healing your self while battle for the board. If you can, start agressive, so rogues will get low value from Blade Flurry, Tinker's Sharpsword Oil and even their Preparation. Be aware of Sap when droping big minions and Injured Blademaster + Circle of Healing. Try to exhaust their resources fast, so they will lose because they will not have any other win condition (if you ever played Control Warrior against the Oil Rogue, you know what i mean). It's a hard matchup, but not impossible.
If you're have trouble with a specific matchup, post something and I will try to help.
The tech cards should took the place of one Thoughtsteal.
Shadow Word: Death -> I don't recommend two SW:D because heavy and slow Control decks are not so popular these days. But, if you are having trouble with them, you can use a second SW:D (instead of Holy Nova, i suggest, except if you're having trouble with Paladins).
Big Game Hunter -> Same as SW:D, but in that case, just use BGH if you're facing A LOT of Handlocks or Ragnaros. Big Game Hunter misses some threats that SW:D can kill (like Sneeds, Kel Thuzad, Tirion, etc..)
Earthen Ring Farseer -> Why? Because it have amazing effect with Auchenai, can heal you against aggro, and its a good body on turn 3.
Harrison Jones -> The 'fashion' card of the last seasons. Why i don't use it as a staple? Because I have a bad winrate against Rogues even with Harrison, and Paladins and Warriors are not a big problem. But, if you are facing a lot of Rogues and Warriors.
Kezan Mystic -> Amazing card against those Control Mages that are around there lately. It works against Mech Mages and Hunters as well.
Velen's Chosen -> Its a good card, but i took it off because many times i was like.. three turns with a dead card in my hand because i have better drops/plays or don't have a minion to use it.
Ysera for Sneed's Old Shredder or Troggzor the Earthinator - Both good threats and are off the range of BGH. If you don't have any of them, use Ragnaros the Firelord or Dr. Boom. In case of any, a second Mind Control.
Sylvanas Windrunner for Harrison Jones or Gaslowe or Toshley. They all have different functions, but are good cards. Gaslowe synergys well with your spells, and Toshley is an amazing body and effect for it's cost. If you don't have any, a second Cabal Shadow Priest or a second Sludge Belcher can be used.
For more replacements, just post what you don't have and what you have and I answer you.
Here's a video of the user EvilQoo playing my deck (before update) against a Mech Mage in the early ranks.
If you have any doubts, please ask! I'll try to answer as soon as possible.
Update 17/03/2015: -1 Holy Fire, -1 Velen's Chosen, -1 Holy Nova, +2 Zombie Chow, +1 Lightbomb. Shorter deck and most effective against aggro AND control, since Zombie Chows provides better early and Lightbomb owns control.
Update 03/03/2015: I got a lot of views in these 3~4 days, so i decided to rewrite the guide with more precise information, tech cards and stuffs.