At this point I don’t think anybody is surprised that the big bad on Innistrad was Emrakul. Chaz wrote a pretty cool piece for us back in February calling it, and scatologists worldwide identified the eldrazi droppings featured in the art of Thraben Inspector. Now we know not only that Emrakul is the big bad, but also what exactly Emrakul does.
Is she castable?
Immediately, given the cost reduction ability it’s hard to say exactly how much mana it will take to hardcast Emrakul. The starting rate is 13, though there are seven Standard-legal card types, so theoretically Emrakul could be cast for six. Six mana is definitely doable, though I imagine that eight is going to be a more realistic low side, and nine or ten being where you get stuck in a lot of games. If Eldritch Moon provides more self-mill effects then Emrakul could be a castable build around card, and currently Vessel of Nascency is a very good start for such a deck.
Is she good if castable?
This is the more important question, and for my money the answer is a resounding yes. Not only is a 13/13 with flying, trample, and protection from instants a lot of great text for a permanent, but Emrakul’s ability is also great. A lot of people seem to be getting hung up on the fact that the opponent gets an extra turn after you take their turn, but all that this means is that the extra text on this body is less good than Mindslaver. There is a lot of space between something being objectively bad and this reality. If Emrakul ends up being consistently castable on six, I would expect to see a lot of turn six concessions in Standard.
How does she play with Nahiri?
With Nahiri, the Harbinger being the other antagonist of the story and Nahiri playing very well with Emrakul, the Aeons Torn, it’s not surprising that there’s already a lot of discussion about how Nahiri will play with Emrakul, the Promised End. The game ending potential of this combination isn’t as high as the Modern equivalent, but once again this is a rather silly reference point. If you feature Nahiri in a deck that can otherwise deal damage, hasting out a 13/13 creature with flying and trample can definitely just win the game. If your deck isn’t about dealing damage, then Nahiri’s ability just puts the Emrakul into your hand after you tutor it up and attack, allowing you to potentially cast it the next turn. And the first Nahiri that hits your graveyard reduces Emrakul’s cost! I imagine that these two cards are very likely to appear in the same Standard deck.
For now, we don’t really have data on what the price for Emrakul will be, though I imagine pre-order prices will be high and Emrakul will be either great or excellent in Standard. With more delirium support there is likely to be a deck that just tries to cast Emrakul, and even if Emrakul were the only card in the set I could imagine a Nahiri Emrakul deck being viable. Emrakul is also a maybe in Modern Tron, which wouldn't surprise me in the least given the power boost that a Mindslaver effect gains in such an efficient format, not to mention the fact that it's a lot easier to cast Emrakul with Tron lands than basic lands.