Hearthpwn

I did'nt play Hearthstone in 20 months and I climbed D10 to Legend with this deck yesterday.  I was an huge fan of Mage (particularly Tempo Mage and Freeze Mage). If you like to play Tempo, I hope this decklist can help you.

Match-ups : 

• Very good : Paladin, Rogue, Warlock
• Good : Demon Hunter, Shaman
• Average : Warrior (excluded bomb), Druid, Mage, Priest
• Bad : Warrior (Bomb only) , Hunter

If you met a lot of Paladin, DH and Rogues, you will climb easily. Sometimes you will met Druids and Warriors, i have a positive ratio against them but games will be long, you shall need to make a low pressure every turn. More easily with Warriors, because Druid still Druid, they can overvalue you despite you made an excellent curve. 

Winrate (at Legend only) :

. 

Match-up precisions : 

Rogue/Demon Hunter : Contest board every turn at the beginning. (Lab Sorcerer or Wand thief in mulligan are precious). Draw when you have the opportunity and a slight control of the board. (after a good firebrand by example). Win regularly comes t8/t9 with a strong board (giants conjuring or by spells), where you can overvalue to finish as quickly as possible the game. Possible to win in late game if the rogue is lucky and counter your giant or a large board, it’s rare but it happens.

Warlock : Same system than rogue/DH but pression is normally less in first turns. It allows to draw more easily. Just don’t overvalue your board too much when you had advantage, rogue/DH can’t counter that but Warlock can. Keep some values in your hand when you accelerate. Maybe the easiest counter (actually I’m 8-0 against them in legend).

Priest/Warrior (excluded bomb) : You should use less cards at the beginning. Your gameplay should be oriented to generate value in mid-game/late-game. The goal is to pressure every turn and not concentrate in one or two. Always keep some cards in hands, excluded if you can make a big Evocation with your sorcerer and finish with a mana cyclone. If your opponent seems to don’t have a good opener and you have a very good curve in hands, you can try to overvalue t3/t4. Honestly it works but be careful, your curve shall give you some cards, the deck hasn’t the power to aggro just by itself.

Druid : Same as Priest and warrior but needs more luck in curve and more focus to had strong cards in t4-t7. You had less time but you can more overvalue your board. Sorcerer Apprentice make some miracles against them cause not controlled (they prefer to ramp and they are punished).

Paladin : Same system than warlock but devolving missiles and Firebrand are more precious. If you had board t4/t and 4-5 cards in hand, usually you won. Be careful to Consecration. Only card in Paladin who can reverse the board in his favour.

Hunter : An hybrid between Warlock and Rogue/DH. Take the board with creatures and counter every turn with your spells.  Not an easy matchup at all cause have a time to draw is difficult. Be careful at Unleash the hounds. Lost many games cause of that.

Shaman : Don’t like play against them. Matchup on paper isn’t bad but take the board against them is so hard. At the contrary, win could be super easy if you have good curve opening. Generally games are with a tactic near to Priest with value every turn and some accelerations at moment.

Mage : Curve. Curve. Curve. If you curve better you increase your winrate chances by far. Don’t focus on draw in priority, it’s a trap. Your opponent will just take his time don’t let him do that.

Bomb Warrior : Pray RNGesus. Honestly I take 100% risk in these games cause if I take my time, I will 100% lose.

Mulligan : Wand Thief ; Lab Partner (single one not two) ; Magic Trick or Primordial Studies ; Sorcerer's Apprentice (not always) ; Firebrand (OK it's turn 3 but rarely regret to keep him trust me)

Key cards : 

Sorcerer's Apprentice : No need to present her if you are a Mage player. The keycard of keycards of this deck. She can launch "Party mode" with Evocation or one spells-card. This mode is possible at every moment of the game, it depends of your hand. My advice, don't wait to long. She can also make pressure in first turn if you are 100% sure she can survive (Against Paladin behind [Mirror Image] by example / Never play this card free against rogue). If she survive 1-2 turns, normally you have highly increased your winrate chances.

Devolving Missiles: You can name that "Anti-Paladin" card. She's still pretty good against warrior (Kargath by example) or rogues (counter to Stealth). Frequently, she will help you to make disappear a big taunt or a creature with too much buffs. 

Cram Session] : At the beginning, I thought this card was bad. But absolutly not. Can easily be an Arcane Intellect at low cost in the beginning. Or be a 3-4 cards draw in middle game. In my playstyle, 70% of the time, I draw 2 cards, 10% 1 card because I absolutly need to draw and 20% 3 cards and more.

Firebrand : His mission : Take the board control at Turn 3 or 4/5. His spellburst should be used everytime to clear the board. You can play it buy curve also to launch the tempo thanks to his 3/4 body. 

Situation cards : 

Ras Frostwhisper : Combo with Lab Partner and Primordial Studies. Can definitively reverse a game, and assure you the win. Love him against Demon Hunter and Druids. Rarely used at turn 6, because didn't draw him frequently but he can be played at this moment without problem for tempo if he's already buff.

Mana Giant : Conjurer's Calling is of course for him. If you launch "Party mode" quickly in the game, you can play one at turn 4 or 5 for tempo too. 

Discover cards : 

Primordial Studies : My preference goes to Azure Explorer (50% of time). Ogre Magi is very acceptable (Yeah, you read it well, 4/4 at T3 with spellpower can make a very good tempo). Bloodmage Thalnos is also pretty good if you don't have creatures at beginning. Astromancer Solarian for long games or no creatures either. Kirin Tor Tricasterin rare situation... but opponents never play around a combo with Ras Frostwhisper.

Wand Thief / Magic Trick: Always plays it with her combo. No "must keep" spells. It depends if you can launch or not a "Party mode" , the board... Honeslty I rarely take a draw spell. Take a spell who can curve or give you extra-creatures for a low cost. Take secrets is not frequent either. I think I never take blast too, except one fireblast for a lethal. Evocation for a long game is a good choice in my opinion.

Replacements : 

Chenvaala in replace of one Devolving Missiles if you met Priest/Druid/Shaman more than Paladin or Rogues.

Additional Information : 

If the deck have sucess i will add some advices. If you have questions i will be glad ton answer it :) Good game all !