The interaction between Doomsday and Shelldock Isle is surprisingly elegant. Once you resolve Doomsday you automatically fulfill the otherwise strict condition on Shelldock Isle, but not only are you allowed to activate Shelldock Isle, you also get to pick what cards will be among the top 4 of your library for Shelldock Isle's Hideaway ability. Even better, as Doomsday also allows you to search for Shelldock Isle in the first place, it is basically a one-card combo!

The Basics

A very simple example of its use is as follows. Consider your opening hand contains Underground Sea, Dark Ritual, Doomsday, you play all three and build:

-> Shelldock Isle, Emrakul, the Aeons Torn, card 1, card 2, card 3.

Next turn you draw Shelldock Isle, play it and hideaway Emrakul. Pass the turn. Next turn you untap Shelldock Isle, draw card 1, and cast Emrakul. Take 1 extra turn. On your extra turn you draw card 2 and attack with Emrakul. Pass the turn again. Untap, draw card 3, attack with Emrakul.

As you notice, you get 2 Emrakul attacks before you have to draw a card from an empty deck and get to draw 2 cards before your first Emrakul attack.

As for the pile you build, it is generally safer to not make Shelldock Isle the top card of your pile. Conjurer's Bauble is a much safer choice, I myself have lost a game 3 because my opponent attacked with Goblin Guide forcing the the Shelldock Isle to go to my hand. This reduced the number of cards in my library and left me with only 1 Emrakul attack. Another reason not to make Shelldock Isle the top card is the 'fateseal' ability of Jace, the Mind Sculptor and similar effects. Whether Conjurer's Bauble is send to the bottom or not is irrelevant, as you will have access to Shelldock Isle either way and Conjurer's Bauble replaces a card to the bottom of you deck (in this instance normally the Doomsday cast to form the pile), thereby not reducing the number of cards. As for your 2 other cards, consider a Dark Ritual and a Doomsday to rebuild a library should you need extra Emrakul attacks, or include 1 or 2 Dark Rituals and a Tendrils of Agony to some gain life or quickly close out the game after 1 Emrakul attack.

The reason that we generally use Shelldock Isle is to hideaway and cast an Emrakul, the Aeons Torn. Emrakul is one of the few cards that, once cast, gives you a very good shot at winning the game on that card alone. Not only will a single blow from the Annihilator 6 paired with 15/15 be enough to directly kill or cripple your opponent, but Emrakul is also uncounterable. This means that if you manage to resolve Doomsday, all other spells you cast for the rest of that game will be uncounterable. However, as Emrakul, the Aeons Torn is also frequently played in other Legacy decks, cards that may answer Emrakul are also frequently played.

Playing around hate

Sorcery-speed hate for Emrakul, such as Oblivion Ring or similar cards as well as the abilities of planeswalkers such as Jace, the Mind Sculptor and Liliana of the Veil can be easily played around. First of all, this is only relevant if your opponent has more than 6 permanents. However, the most elegant solution is to wait with activating Shelldock Isle, pass the turn and cast Emrakul in your opponent's end step. That way, you first get your extra turn, followed directly by your actual turn. This gives you two consecutive turns in which you can attack with Emrakul, without ever giving your opponent another main phase. Another solution is to attack the planeswalker instead of the player, but this may require that you cast another Doomsday to refill your library.

The bigger issue is with permanents that may prevent your Emrakul from attacking the first place, such as Ensnaring Bridge or Blazing Archon. To deal with these you can include a bounce spell in the cards you search with Doomsday. This is also the main reason that many Doomsday lists used to include a 1-off Wipe Away in the sideboard. Also note that we used to play around Karakas, simply by including our own 1-off Karakas in the 5 cards you search with Doomsday and play Karakas right before casting Emrakul. Unfortunately, this doesn't work anymore because the legend rule changed with the M14 rules update. Karakas is currently much harder to play around. It will probably cost you another sideboard card if you really want it, perhaps Pithing Needle or Wipe Away, but if you really want to spend a sideboard slot on this then why not throw in an Omniscience? Spending an entire sideboard slot just to make Shelldock Isle/Emrakul robust to Karakas is a huge investment though, you'd probably only do this if your metagame is filled with UW Counterbalance decks with plenty of Karakases in them.

More difficult hate to play around comes in the form of Wasteland and Stifle. Stifle is particularly nasty as it can counter not only the activation of Shelldock Isle, but more importantly also the Hideaway trigger. Similar to Stifle, an opponent may cast Silence or Orim's Chant in response to your Shelldock Isle activation, although your ability will still resolve you won't be able to cast Emrakul since you're not allowed to cast anything for the remainder of the turn. Also, don't forget about cards that attack nonbasic lands such as Blood Moon or Magus of the Moon, but these can be bounced more easily. Wasteland is also very relevant as we are likely to pass the turn with a tapped Shelldock Isle in play.

In theory, you might play a card that allows you to untap the Shelldock Isle and exploit a window of opportunity when your opponent's Wasteland is tapped or hasn't played one yet. Another possible advantage is that it may speed up your win by a full turn. Many alternatives for this slot have been tested, including Amulet of Vigor, Twiddle, Dream Salvage, and so on, but all are inferior to Cloud of Faeries. The conclusion is that Cloud of Faeries is better for several reasons:

  • It cycles into your pile should you want to kill with Tendrils of Agony after all
  • Saves your Emrakul, the Aeons Torn from Diabolic Edict and similar effects
  • You need only 1 attack when opponent is on 16 and has no flying creatures
  • Cloud of Faeries can block a creature if your opponent has more than 6 permanents

Most people suggesting Amulet of Vigor, think that it will allow them to play around Wasteland, but they don't consider that the opponent can just as well respond to the Hideaway trigger with Wasteland. Both Twiddle and Amulet of Vigor are not cheaper in terms of mana than Cloud of Faeries, this should be obvious. You will find that most lists don't include any Cloud of Faeries/Twiddle/Amulet to go with the Emrakul plan, simply because their use is too narrow. Even if it just takes up 1 additional sideboard slot is by many players considered not worth it.

Theoretically speaking, we already play a card that can be used to untap lands: Time Spiral. However, Shelldock Isle typically removes 2 cards (the land goes to the battlefield and exiles the hidden card) from the cards that will form your new library before you draw 7. If you don't want to kill yourself by drawing 7 cards of Time Spiral, note Time Spiral also exiles itself, you need to have 4 cards in your hand or post-Doomsday graveyard. And that's not including the cards you will draw in the turn(s) that you attack with Emrakul. So this is probably not feasible in practice.

One nice thing is that if you get the Shelldock Isle in hand, if the opponent holds a Surgical Extraction or draws into it for their turn then it does nothing to disrupt the pile as Hideaway digs four cards deep thereby encompassing the whole pile. Be warned however as if you do decide to include a secondary Doomsday in the pile they can extract it off of the one in your Graveyard thereby reducing the number of turns you have before decking yourself by one. The presence of a Conjurer's Bauble can help remove this risk by replacing the targeted spell back into the deck.

Summary

  1. SI + Emrakul is effective when expecting heavy counter magic, once DD is resolved no other (counterable) spells need to be cast
  2. Be careful choosing when to bring this combo in
  3. Be mindful of potential disruption such as Wasteland