Hearthpwn

UPDATE:
02.05.17 - This deck got a lot more attention than I expected. I appreciate all the support and feedback. I will make a guide very soon. Been a bit busy with work.

03.05.17 - It seems like a lot of people doesn't know the win conditions of this deck or even how to play it. First off, it's not a easy deck to play with if you are not familiar with Dragon Priest. It requires some patience and practice. Give it time.

Second of all, people are complaining about how it does not work. It all depends on what kind of decks you play against. Last season there were a lot of Paladin decks and Quest Warriors in the higher ranks, which this deck works great against.

Now for example there are a lot more Mages. You can't just play the same cards against every other deck. Tech/adjust the cards according to what you play against.

Win condition & tech choices/card replacement added.

09.05.17 - Mulligan guide added.

25.05.17 - Due to the change in the meta, some cards have been changed to increase the winrate against some of the Archetypes. 

This deck got me to Legend this season all the way from Rank 20.
Proof - http://imgur.com/a/098MO

The interesting thing about this deck is that nobody expects it. From Rank 10 and down, I never met a single Dragon priest deck. This is of course a great advantage.

It also counters a lot of the meta decks right now. 

It might struggle if you don't get the right mulligan at the start and the deck you are facing is aggro.

Other than that, it might be a bit short on dragons, but against mid-range and control, just keep a dragon in mulligan.

Against aggro, potion of madness and Radiant Elemental along with Oracle is great.

If this deck gets enough likes, I will write a mulligan guide and a guide on how to play against other decks.

This deck does really good against Paladin right now, and since its popular atm, I met a great deal of them and had a really nice winrate against them.

The Potion of Madness and Shadow Word Pain is great against Warleader and Murlocs. The Ooze along with Shadow Word Death just destroys Tirion. And Drakonid is still a great card. Along with Lyra and Combo you just get so much value in the longer games.

Really fun deck to play with btw. Lot of discover cards, which makes it more flexible.

Ooze is the biggest tech card here, but you could bring inn a Crawler or Crab instead of one Oracle if you meet too many Murloc Paladins or Pirate Warriors.

Any tips to improve this deck would be appreciated.

Mulligan and Class Guides:

Mulligans:

VS Aggro:
Crystalline Oracle, Northshire Cleric, Potion of Madness, Radiant Elemental and Shadow Word: Pain.

*Keep Power Word: Shield only if you already have Radiant Elemental or Northshire Cleric.

*Keep Gluttonous Ooze against Pirate Warrior.

VS Midrange:
Crystalline Oracle, Northshire Cleric, Potion of Madness, Radiant Elemental and Shadow Word: Pain.

*Keep Kabal Talonpriest if you already have a minion/minions and a good curve.

*Keep Netherspite Historian only if you have a Dragon.
 
*Keep a Dragon if you have a good hand.

VS Control:
Crystalline Oracle, Northshire Cleric, Potion of Madness, Radiant Elemental and Shadow Word: Pain.

*Keep Kabal Talonpriest if you already have a minion/minions and a good curve.

*Keep Netherspite Historian only if you have a Dragon.

*Always try to keep a Dragon.

*Against other Priest decks always keep Twilight Drake.

Win condition:
The normal win condition for this deck is to out value your opponent. This deck has so much value that it can out value almost any deck. The exception is of course Jade.

Lyra the Sunshardalone is another win condition. This card must not be rushed and should only be played when you have combinations ready. 

Drakonid Operative is another card that can create win conditions along with Netherspite Historian. These cards are the reason why Dragons still works. People are asking why Ysera isn't in the decklist, its because you don't always need it. But when you do, you can discover it.

Against aggro decks:
You play to survive. Keeping the board clear is vital. It's also important to have minions on the board when possible. Cards such as Potion of Madness and Shadow Word Pain along with Radiant Elemental and Shadow Word Pain are very important in these matchups. Oracle, Northshire Cleric and Kabal Talonpriest should be used as bodies too. When you gain control of the board and they run out of cards to pressure is when you win.

Against mid-range/tempo decks:
You play for the board. This is were you get the most out of the discover cards in the deck. Again, it depends on what kind of deck you play against, so it's important to pick the cards you need rather than the strongest cards, like Ysera, Deathwing etc. It's important to play on curve and use the spells wisely. Always plan your next moves before you play. Lyra is also a gamechanger when it looks like you are losing. It has saved me many times.

Against control/late-game decks:
You play to out value other decks. Against Jade Druid you need to be the one that pressures. If they get too big Jades and/or plays Earthen Scales on big minions, you will lose. Other than Jade, this deck should out value most other decks. You want the game to end before fatigue thou, which it mostly will due to the opponent running out of AoE cards.

Tech choices & Card Replacements:

Tech Choices
The deck has 2-3 cards that can be changed to improve winrate against certain classes. These cards are Crystalline Oracle, Gluttonous Ooze and a second copy of Potion of Madness.

Priest of the Feast vs Mage decks
Dirty Rat vs Quest decks (Warrior, Rogue and Mage)

People have also suggested Ysera and Elise the Trailblazer. I haven't tested this, but they are certainly viable choices too.

Card Replacements:
Acidic Swamp Ooze instead of Gluttonous Ooze
Elise the Trailblazer instead of Lyra the Sunshard