Conditions Allow - Winter, Cynical Opportunist EDH
(Winter, Cynical Opportunist Art by Andrew Kuzinskiy)
Winter Delirium
Magic: Foundations is barreling towards us, but there's still plenty to explore within the house of Duskmourn. Of all the house's many denizens, there is probably no one better suited to guide you than Winter, Cynical Opportunist, so long as you leave him before he leaves you.
Winter, Cynical Opportunist is a 2/5 with deathtouch for that lets you exile any number of cards with four or more types from your graveyard at your end step to put a permanent among them into play with a finality counter. He also feeds your graveyard by milling three cards whenever he attacks.
With five toughness and deathtouch, Winter, Cynical Opportunist can usually attack, but he'll need a little extra help if you want to hit Delirium every turn. In fact, it'll take more than a robust self-mill package to accomplish that. Any Winter deck will need to include an even spread of card effects that fill all the rolls a Commander deck needs, from lands to battles.
Filling the Graveyard
Most Commander decks want to ramp in the first couple turns of the game, but reanimator decks don't need to cast their big spells. Instead, they want to get them into the graveyard quickly with the help of Stitcher's Supplier, Mire Triton, and Mulch. This is especially true for Winter, Cynical Opportunist since his ability triggers in your end step. Your goal is to have four card types in your graveyard by turn four, so Winter can reanimate something impactful as quickly as possible. To that end, I'm also including Codex Shredder, Grisly Salvage, and Nyx Weaver. The most useful early creatures are Stitcher's Supplier and Millikin since they both mill and provide extra mana.
The next most important set of cards for this deck are ones with two types. These help to minimize the number of cards you need to exile from your graveyard to hit the four card types, which also means you get to bring more permanents back with Winter. Grist, the Hunger Tide is just a planeswalker on the battlefield, but she also counts as a creature while in your graveyard. Shigeki, Jukai Visionary is not only a self mill engine, but he can also rebuy key spells that Winter, Cynical Opportunist can't retrieve, like Grisly Salvage or Assassin's Trophy. Finally, Gravebreaker Lamia only puts one card into your graveyard, which lets you find the exact card to reanimate to take over the game.
Interacting With the Locals
All this mill is well and good, but you need to hit something worth reanimating as well, and the bigger the better. Noxious Gearhulk and Cityscape Leveler both have two card types, and they help you apply pressure while also removing a creature or two along the way. Necron Deathmark fills that roll as well, while also milling you. Of course, Winter, Cynical Opportunist doesn't just bring back creatures. Kenrith's Transformation draws you an extra card, while Lignify hits that "two card type" sweet spot.
Of course, the deck can't be all permanents. Building around Delirium means you need to hit as many card types as possible. Eyeblight's Ending has two, but a little Delirium is no reason to turn away more efficient options. Assassin's Trophy hits anything that needs going, while Go for the Throat is among the most efficient creature removal spells around. I've also been very impressed with Blessed Respite as a piece of graveyard hate, and for graveyard decks it can also act as protection against opposing graveyard hate, letting you shuffle your own graveyard into your library before any key cards fall into an unfortunate Bojuka Bog.
Heavy Hitters
Part of the fun of playing reanimator, however, is reviving big, splashy creatures that are too expensive to cast, not just casting glorified Doom Blades for free. These cards are highly customizable to what you want to play, but there are a few factors to keep in mind. First, Winter, Cynical Opportunist pulls cards from your graveyard during your end step, so cards with enter the battlefield abilities are more valuable than haste-y creatures. For this reason, I'm including both Overlord of the Balemurk and Overlord of the Hauntwoods, since their abilities trigger when they enter and again when they attack on your next turn. Demonic Covenant, on the other hand, is much more awkward. It also triggers at your upkeep, so it won't do anything until the end of the turn after you bring it back, but making a 5/5 flier that draws a card every turn is pretty good, so it'll make the cut as well. Finally, Demolisher Spawn is a thematic Overrun effect for this deck that turns your medium-sized utility creatures into real threats.
Another important aspect of Winter, Cynical Opportunist's ability is that your permanents come back with finality counters so that they'll be exiled instead of destroyed. This stops you from bringing them back again. In order to get around this, I'm including Springheart Nantuko, which you can bestow onto a powerful creature in order to make token copies of it every time you play a land. One Demolisher Spawn is bad enough, but two or three are nearly unstoppable.
Alternately, you can lean into Winter's exile effect and use Whip of Erebos for quick bursts of power throughout the game. Graveyard decks are often shy about letting their big threats get exiled, since a large part of the archetypes strength comes from the fact that their creatures simply don't stay dead. Winter, Cynical Opportunist forces you to consider reanimation slightly differently, however. You can't bring the same threats back over and over, so you need to press your advantage quickly, before your opponents can respond. Whip of Erebos complements that playstyle perfectly, whether you bring back Mire Triton for a little extra mill or Greater Tanuki for a big life point swing.
A Little Extra Value
Rounding out the deck are a few smaller cards that ensure you hit your land drops and keep up with decks trying to go wide. Token-makers, like Bitterblossom and Formless Genesis, are also extremely powerful with Demolisher Spawn. The most important thing about these last few cards, however, is that they are all two types. As always, this ensures you hit Delirium easily, even while exiling at least two cards from your graveyard every turn.
Winter, Cynical Opportunist requires you to do a little more work than other reanimator commanders, but if you can get all the pieces in place he's capable of some powerful moves. He also forces you to reconsider how you play a reanimator deck. Whether you're trying graveyard shenanigans for the first time, or looking for a new, unique twist on the archetype, Winter, Cynical Opportunist may be what you're looking for.