I love playing Mage, it is my most played class. This deck is relatively standard but with a few important tweaks that combat the legions of Kazakusan Druids in the current meta, and prove pretty handy against the Face Hunters and Libram Paladins doing the rounds from Diamond 5 to Legend at present.

Mulligans

I always keep Wildfire because it is the basis of the deck - the sooner you smash out enough ping, your old mate Mordresh Fire Eye becomes live. Mordresh is just a phenomenal card in this deck for lethal, clearing a heavy board, and can be duplicated with Potion of Illusion occasionally, which folk don't see coming.

For anything aggro (could be an aggro Druid, Face Hunter, some Shammys, Shadow Priest) it is worth keeping a cheeky Fire Sale

Arcanologist is a no-brainer to keep. It helps us build the armour that enables us to beat fast-paced decks, and gives us a bit of lastability when the Druid pops off with his Kazakusan, as well as giving a bit of body on the board for some early damage or clears.

You can't go wrong with holding on to Flightmaster Dungar. Depending on the match-up and how you think it will pan out will determine how you use it. I never used the turn 1 option, more often than not I went for the 12 damage after 5 turns. Against extreme aggro that tapers off I sometimes used the 10 heal after 3 turns to get through the initial onslaught.

If I think the opposition may be token based - some Shammys, Paladins, Token Druid, Face Hunter - I sometimes gambled and kept a Reckless Apprentice. It is always a solid keep against a token deck when you have a Wildfire.

Against a Paladin,  Priest, or Dragon Druid, a well-timed Mass Polymorph can be critical. For that reason, I occasionally kept this card. If you can follow up afterwards with a Grey Sage Parrot to clear the secondary board they baited you to get played then this can destroy the soul of your opponent. The Arcane school synergy with [Hearthstone Card (Magidster Dawngrasp) Not Found] is one of the reasons I only run one Arcane Overflow, and if you need to rerun your sheeping with the Magister it is wise to hold back on playing Overflow, great tempo removal though it may be.

Magister Dawngrasp is a card I sometimes keep in a mirror match up, as whomever can get the big hero powers going is often the victor.

Against the aforementioned aggro token-based decks it can be good to have an early Shivering Sorceress on the board. But beware - the unique selling point of this card is the reduction in mana cost for one of your big spells. I tried a few times to tempo this out on turn 1 without a spell to reduce, or with a same turn follow up of a reduced  Wildfire, but this never ended happily for me. A turn 5 coined out reduced Mask of C'Thun followed by a parrot on turn 6 is hard for any class to resist. Try to get value from our shivering friends.

Amplified Snowflurry is a usual keeper. Some early chip damage and a potential freeze of an enemy hero or minion. Just be careful - if you have no turn 3 play but to hero power it is best to just fire off the freeze hero power on the same turn you play the Flurry - as counter-intuituve as that may feel sometimes. That extra one point you have squeezed in can often be the difference between winning with a turn 7 or 8 Mordresh, and crying into your cup of tea.

A few key cards and the reasons for their inclusion:

Mutanus the Devourer is there plain and simple, to eat an opponents big boys. If I was to remove one card from the deck it would likely be this one. I had kept him in to eat an over-eager Shammy's quest reward, but they have been few and far between for me since the Druid onslaught began with the mini-set. Let's face it - you aint eating Kazakusan with it, because they've already cheesed it out on turn 5. I left out Rustrot Viper for this, because I found I was not facing weapon-based decks any more and the Libram Pallys were manageable even with the half damage from their hero card.

Potion of Illusion is just the unexpected crown jewel of the deck. No one expects this or plays around it. You can have a lot of fairly cheap minions on the board on turn 6, and being able to replay an apprentice for a board clear, or a Deepwater Evoker for some extra armour and a spell draw, can be game-changing. Even a one cost parrot to replay a big spell can be a major tempo shift in your favour. Ultimately, getting a second Mordresh is the pot of gold at the end of the rainbow, and this won me a few games after my opponent froze him and ignored him, or sat a big row of taunts in front, only to repent at their leisure!

Taelan Fordring - get you your Mordresh and protect your face. Pulling out the Clumsy Courier is a decent consolation if you already have Mr Fire Eye.

Clumsy Courier is there to get an early Rune of the Archmage into play. Be careful if you are looking to get value from your parrots, depending on what spell you want it to repeat would determine how you play your Courier. A few times I blundered out my Mask with the Courier only to regret it when the extra 10 damage from the parrot didn't materialise. There are some match-ups where consecutive Runes is a life-saver, such as our Dragon Druid friends, but generally if the opponents board is empty or your hand is nearly full, Rune can be more hindrance than help (burning cards and killing your minions), which is why I like to cheat it out with a courier and keep my parrots for Mask or Polymorph.

Varden Dawngrasp may seem like a luxury, but it is worth the inclusion in my view. At the very worst it is a turn of stall to look for an answer, but often it gives you the leeway to ping Mordresh active to clear a big board. If you are lucky he may even be still alive to bump off a divine shield before playing a clear.

Potential Opponents

Druid - keep a Fire Sale in case it is aggro, but usually it will be Kazakusan. Get early tempo on the board, deal that critical early chip damage, rack up the armour, hope for Wildfires and Mordresh. Plenty of armour (a good couple of evoker draws, maybe 3 or more Ice Barrier) and a timely Mass Polymorph or 3 to clear those pesky minions with (summon a legendary minion) deathrattle, can be helpful. From Diamond 3 to Legend I found these to be nearly every other game and they were very beatable. I think that people are still not playing this deck optimally due to how new it is, and the RNG from the treasures can sometimes lead to an insta-rage-quit.

Hunter - Similarly, enough armour gain to get past their initial burst will win you the game. Fire Sale can clear early board, Apprentices and Wildfire likewise. You know what it's like - if they hit the nuts very few decks will beat them, but I was never too worried by them. A sneaky Overflow can remove a minion snowballing with buffs, but it can be a risky keep.

Paladin - I found them very manageable. Early removal will let you start to build a board, which you can then chip away with and pull the minions back into your hand hopefully, with a timely Potion. Judging when to Polymorph can be critical, and not playing another spell over 5 cost to get the benefits again with a parrot when they inevitably Liadrin and play them all again is also something to be aware of. You could always tech in a Viper for extra comfort if you face a lot of these.

Priest - Didn't face many. Generally a fairly easy win unless they are lucky with their quest, or with draw if they are shadow. Was expecting to face more Dragon Priests, but they never materialised. Your pings, Masks, and a coup-de-grace of Mordresh should send them packing. I tend to conserve my damage to send it our in bursts to stop them drip healing through the early turns. Holding on to your big guns until you can play them in successive shots (Mask, Parrot+ping, Parrot+Wildfire+ping, Ping+Mordresh for example) can prevent them from rallying.

Rogue - Only faced 3 in 114 games played in total this season. Just playing your curve without any special tweaks should do it.

Conclusion

This is a really fun deck to play, but let's not be kidded - it is not free from RNG. Rune of the Archmage is often a big play that can determine the outcome. Will you get that Polymorph or Mask? Or will you overdraw and burn your Mordresh? You've got to be smart with the timing and circumstances to get the most out of it. Like I say, try to play it when the opponent has a tasty board, and your hand is sitting at 6 or less cards. You can almost guarantee it will either freeze or slay the board. If you play it smart you can ensure that even a crap selection of spells will at least not hinder you.

Dungar and Potion are not mainstays of this archetype, but I would say they are unsung heroes. Maybe it has just been my luck - you know what Hearthstone is like! - but that extra 12 damage on turn 7, or the healing to bring you back from the brink for a few more turns can be life-saving or match-winning. Similarly, your potion pulling a couple of Apprentices back into your hand for a hail mary with a boosted Magister hero power is awesome.

I hope you can have some fun with this deck and fight off the swarm of Druids you will no doubt be facing!