Just killed a warrior on turn 6 from 33 health with nothing but a Necrium Blade on board
Edit: thanks for the upvotes. Here's a small description:
The deck's idea is to assemble the whole combo through a single Elven Minstrel. That happens 100% of the time when you do not play the Cavern Shinyfinder, however i have found that card to add consistency rather than lower it.
The way you actually win is by having a 1 charge Necrium Blade equipped, then playing Kobold Illusionist -> attack > Backstab (or Razorpetal) the Illusionist and then burn the opponent. That's 4 mana for 2 copies of Malygos. Shadowsteps only help prepare a 2 mana Illusionist, leading to an even cheaper setup, that can allow us to burn even a high armor opponent. They are however not highly important and are probably the first cards to replace.
Cards like Bloodmage Thalnos, Vilespine Slayer or some taunts would help keep us alive, but would lead to us needing more time and more draw. Personally, i have not found that version of the deck as interesting or effective.
Edit #2: i've replaced the two Shadowsteps for one Sudden Betrayal and one Necrium Vial, as a test. The first is aimed at helping against aggro and the second against high armor decks (and slow draws).
As for Mulligan choices: Always keep one Elven Minstrel, as he gets us the full combo. Mulligan aggressively for him.
If you are certain the opponent is playing aggro, you can keep effective removal like Backstab or Sap. If you are certain they are slow, keep Preparation and Razorpetal Volley, as they speed things up for you.
I replaced the Shinyfinder with a second Sudden Betrayal, partially because the secret was performing well, partially because of a rage moment on a shinyfinder topdeck on the wrong turn.
I am personally getting close to a 50% winrate against zoo, which should be a very bad matchup. Don't play like a typical control deck. When the pressure is not too high, try to ignore it and setup your combo. You have to win first, not outlast them.
Thank everyone for the enormous feedback. This is something i never expected. I hope you keep having fun!
I do not have the time to refine this deck as much as I would like. However as many of you have found, tuning it is not too hard, because there are a few simple guidelines to follow.
1. You should be very careful about adding more minions. Every one reduces the effectiveness of Elven Minstrel by a lot, and that card is the soul of the deck.
2. Mulligan almost everything for Elven Minstrel and go for the combo as soon as possible. If your opponent doesn't have lethal on board and you can set up the OtK, go for it. Don't play this as control because the rogue class does not have the tools for that.
3. Don't give up if your opponent is gaining a lot of armour. If you find the right spells you can burn through obscene amounts of it, as demonstrated in the videos.
And an important clarification. The deck has a somewhat weird approach to it. Contrary to what most players are used to, the aim is not to have a fair chance to win every game. Instead the deck aims at being extremely favoured when drawing properly, while accepting that there will be a few games you just concede. It is in a sense a coinflip deck, except the odds depend on the metagame, rather than always being 50-50.
The deck is now much smoother and can actually be used for ranking up consistently.
Here's a video of the deck by Kiwiinbacon.
And here is the second video!