Funnest deck ever! General idea is to out value your opponent with copying Elise's pack.
Great deck for fun and even for ladder (i played this deck a bit on rank 5, had around 60% WR last month, up to 70% now).I hit rank 3 last season after playing it in most of my rank 5-3 games.
Always keep those Northshire Cleric and Mana Geodes in Mulligan.
against warriors always act like your opponent is a pirate warrior (in mulligan), there are more of them and if you don't and it is one of the pirates, you lose.
Against Aggro- (Warrios/Druids) keep potion of madness in mulligan too, throw everything that doesn't serve you well in the early game. against aggro forget about out-valueing your opponent, it's going to be all about staying alive.Heal Mana Geodes for getting trade-able 2/2's, Try to get Priest Of The Feast with a lot of spells and maintain board control. Try to taunt up with your Tar Creepers and buff their HP so you opponent will have to trade a lot of minions for them, if he can't kill them heal them every turn. Shadow Word Pain OPOP.
Against Rogues- you can't know if it's miracle or Quest, so you will have to mulligan against the Quest's early game (Mulligan like vs aggro). Use your Holy Nova against their board before they use the quest, if you succeed in wiping the board before they use the Crystal Core you get a lot of value.
Try to get Dragonfire Potions in hand (by draw) and from Shadow Visions, they will wipe off the Rogue's board again and again.
In this matchup saving cards for lategame (like saving shadow visions for Elise packs when in control matchup) is the wrong play. you will have to throw all of your cards early-midgame to survive it.
Against Miracle Rogues, they can't do anything to you, this is an easy matchup
Against Control- FINALLY SOME FUN! this match up is so funnnn you just help them waste the time and wait for a late turn, maintain your board control until the later turns with Mana Geodes Northshire Clerics Tar Creepers and Talonpriests.
In Mulligan, somestimes I kick 3 drops and Mana Geode, it is ok not to have a good early game here it does not matter (if you are vs warrior so you mulliganed against aggro, that's great bcs you are going to want the 3 drops and Mana Geodes here [against the turn 4-7 quick taunt drops]). I like keeping Lyra here.
late game?! here comes the pack creation/Medivh ultimate VALUE. you Elise and start Shadow Visioning your packs, then you Lyra combo and you get more Shadow Visions (even if not, even 2 packs is a huge value). You can get more Free From Ambers from Lyra. When you Medivh-Free From Amber you get such a huge board for a 8 mana spell that you are in a decent situation, when you do it again your opponent cries.
Against Midrange- Hunter- same as aggro :/ calling that midranged is a lie.
Mulligan like control, Just be a bit more aggressive, do not throw the 3/2 drops, but you don't NEED the 1 drops and a nice little Geode for turn 2. Survive until the lategame and boom, outvalue them with Elise,Lyra,Medivh into winning.
If you have any questing and things you want to know about this deck, or thing you want me to add to this guide please write it at the comments and I will answer everything.
Card Replacements (epics/legies/adventures)
Mana Geode- Wild Pyromancer/Potion Of Madness. If you are facing a lot of pirate warriors you can try Ooze/Golakka Crawlers. If you are facing to much Quest Rogues then Dirty Rat should work.
Dragonfire Potion- you will now start losing to Quest Rogues... to bad... I think that doomsayers will do, or another Free From Amber (for Medivh), MB 1 Holy Fire (really bad though).
Medivh- go buy Karazhan! NOW!! xD no but seriously just go and buy Karazhan.
I guess you can replace this with another Free From Amber, but this is really bad.
Priest Of The Feast- go buy Karazhan!! NOW!!! you will KYS when in aggro match-up now :(
I suppose that Greater Healing Potion/ Darkshire Alchemist/ 1 Holy Nova (if you don't have 1 from earlier, other replacements are preferred.)
Cabal Shadow Priest- Mana Geode and it's replacements should work out.