Hearthpwn

So there are multiple ways to achieve the glory of Mecha'thun's Deathrattle.

But first of all this deck is for fun and not for grinding to legend.I just want to share my idea of a Mecha'thun Rouge Deck. 

So here are the possible combos:

Road 1: WANTED! (adds a coin to your hand) + Mecha'thun + Preparation + Walk the Plank

Road 2: If you get the Coin you can use the coin generated by WANTED! to play some cards earlier or to trigger a combo card.So the combo is: Coin + Mecha'thun + Preparation + Walk the Plank

Road 3: If you have used both of your Walk the Plank cards for board clear,you can still win the game by triggering Mecha'thun's deathrattle by using Necrium Blade.Just play Necrium Blade and attack once,so you can trigger Mecha'thun's deathrattle the next turn by simply attacking another time.You can even make this combo,if you are low on health an not able to attack because of a taunt minion by equipping one of the Shadowblades.Important for this combo is after you have played [card]Valeera the Hollow[/card] , keep in mind the "Shadow Reflection" does count as a card as well,so you have to save a Coin so you can play Coin + Coin from  "Shadow Reflection" then Mecha'thun and then attack with Necrium Blade (with one durability left) or have Necrium Blade equipped,play Mecha'thun and hope he survives until your next turn,then play  Coin + Coin from  "Shadow Reflection" ,then Shadowblade to trigger the combo.     

[Edit:Ups,you can't trigger  Mecha'thuns deathrattle,because he is still on the board. I forgot about that :D This happens,when you spontaneously add a new way without trying it out. Thanks to user-100248567]

Road 4: If you have no coin left and already used your extra coin from WANTED! (for example: to play Valeera the Hollow , you still can pull off the combo.Play Mecha'thun , Shadowstep him and then play the turn after Mecha'thun (for 8 mana because of Shadowstep) + Preparation + Walk the Plank

IMPORTANT! : If you have played Valeera the Hollow you have to use  Preparation twice (your normal one and the "Shadow Reflection") because the "Shadow Reflection" count as a card aswell!     

Board clear tools: Shadowblade , Walk the Plank , Vanish , Fan of Knifes , Zilliax and WANTED! 

Card draw:  Fan of Knifes , Raiding Party , Elven Minsrtel , Gral,the Shark and Myra's Unstable Element

I think Shadowstep is a nice addition because you have an additional way to pull off your combo (look Road4), trigger Prince Keleseth twice, get an extra taunt minion out of Stonehill Defender (old version with "Stonehill Defender), use  Elven Minsrtel again to draw two more cards, get an extra Saronite Chain Gang or you can play Zilliax again.You can even use Shadowstep to bounce Gral,the Shark, if you have your combo already in hand,so you can "eat" another card from your deck to reach fatigue faster.  

Sometimes you don't even need to pull off the combo because of an early Prince Keleseth,which is in some cases enough pressure to finish your opponent.

Hope you like it and If you have some constructive criticism for me,I would be happy to hear them.

 Have a nice day and a happy new lunar year^^