Affinity MTG: How It Works, All 77 Cards, the Artifact Math and a $55 Emry Deck (2026)

Affinity is the Magic: The Gathering keyword that makes a spell cheaper for each permanent of a certain kind you control. “Affinity for artifacts” means “This spell costs {1} less to cast for each artifact you control.” Control four artifacts and a Frogmite, which costs {4}, is free. Colored mana still has to be paid, and the spell’s mana value doesn’t change.

The rule is simple. The hard part is reaching the artifact count. 77 cards have affinity, and 37 of them count artifacts, and on those 37 cards 81% of the printed mana is generic. So they are priced on the assumption that you already have artifacts in play. We ran our own deck and all 181 Commander precons through test games to see how many you really have by each turn. By turn 8, our deck has four or more artifacts in 95% of games. The average precon gets there in 12%.

This guide covers the affinity rules, the artifact math, the trick of counting an artifact and then spending it, all 77 cards, how the Affinity deck got eight cards banned from Standard, the best commanders, legality in every format, how to beat it and a $55 Emry, Lurker of the Loch Commander deck.

What is affinity in MTG?

Affinity is rule 702.41 of the Comprehensive Rules. Rule 702.41a says it’s a static ability that works while the spell is on the stack, and that “affinity for [text]” means “this spell costs {1} less to cast for each [text] you control.” Rule 702.41b says that if a spell has more than one instance of affinity, each one applies. Four things follow from that:

• It only reduces generic mana. Thoughtcast costs {4}{U}. With any number of artifacts, you still have to pay {U}. That colored part is the spell’s floor.
• It doesn’t tap anything. Your artifacts count just by being there, tapped or not, so they can still attack, block or make mana.
• It counts permanents you control. Your opponents’ artifacts don’t help, and neither do artifact cards in your hand or graveyard.
• It doesn’t change mana value. A Myr Enforcer you cast for free is still mana value 7.

“Artifacts” is only the most common version. Affinity can count 32 different things, from Forests and Slivers to Foods, Equipment and tokens. The rules are the same for all of them, so everything here applies to Polliwallop’s affinity for Frogs as well.

Affinity rules: 15 common situations

The affinity math: what each artifact is worth

Every artifact you control takes {1} off each affinity spell you cast that turn, not just the first. The table shows what seven notable cards cost at each artifact count.

Across the 37 “affinity for artifacts” cards, the average mana value is 6.92, the average generic portion is 5.59 and the average floor is 1.32. Eight of them have no colored mana at all and can be cast for free: Frogmite, Myr Enforcer, Sojourner’s Companion, Frogmyr Enforcer, Panther Robot, Mycosynth Golem, Tooth of Chiss-Goria and Scale of Chiss-Goria. 12 have a floor of one mana, 14 have a floor of two and three have a floor of three.

Here is how affinity compares with the other keywords that lower what you pay:

Card for card, affinity is the strongest of the four, because it spends nothing. That’s also why its cards have high printed costs: their prices assume you’ve built the deck to support them.

How many artifacts will you really have?

Most affinity guides stop at the discount. What matters is how fast the artifacts arrive, so we tested it. We goldfished our Emry list below 100,000 times, then ran each of the 181 Commander precons in our precon database 2,000 times. Every game has a 7-card hand with no mulligan, one land a turn, no opponents and nothing dying or being sacrificed. All the deck’s mana goes to its artifacts, cheapest first (plus four Thopter makers in our list), and the commander isn’t cast unless it’s an artifact.

By turn 8, our list averages 7.0 artifacts and the average precon averages 1.7. In that precon, Thought Monitor at {6}{U} still costs five or six mana on turn 8. In our list, it costs about one or two. Treat this as a guide rather than a forecast. The test ignores tapped lands, which flatters both columns a little. It also leaves out Treasure and Clue tokens in the precons, and those would raise their numbers, while our list’s card draw and Emry’s recursion aren’t counted either. And it spends every mana on artifacts, which no precon would do in a real game.

The precons also show how many artifacts you need. The median precon has only 10 artifact cards out of 100, and the range runs from 1 to 50:

So the number to aim for is 30 or more artifacts, and ideally 40. Below 20, even a good affinity card is a bad buy. If your deck has only a handful of Signets and Equipment, Thought Monitor will rarely cost less than five. If you’re adding a few artifacts to a deck now, start with the best mana rocks, because they count toward the discount and pay for what’s left.

Count it, then spend it

Rule 601.2 sets the order for casting a spell. You work out the total cost in 601.2f, make mana in 601.2g and pay in 601.2h. So an artifact you spend for mana has already given you its discount. The official ruling on Tezzeret, Master of the Bridge says you can “lock in a discount for an artifact you control and then sacrifice that artifact to activate a mana ability.” In practice:

• A Treasure is worth two mana. It takes {1} off, then you sacrifice it for one mana of any color. With three Treasures, Thoughtcast costs {1}{U}, and those same three Treasures can pay for it with one mana left over.
• Sol Ring is worth three. It takes {1} off and then taps for {C}{C}.
• An artifact land is worth two. Seat of the Synod lowers the cost by {1} and then taps for {U}.

With Clues, Foods and other token makers, every piece also counts for each later spell that turn. The Commander card pool has 348 cards that make Treasure tokens, so a deck can build up a discount without playing many artifact cards.

All 77 affinity cards

Here is every card with the affinity keyword, sorted by how many Commander decks play it on EDHREC (pulled 7 November 2026). Affinity debuted in Mirrodin in 2003, and 20 of the 77 came from the original Mirrodin block in 2003 and 2004. Then it went quiet: only one more card appeared before 2019. 56 have come out since 2019, and most of the newer ones count something other than artifacts. Prices are the cheapest ordinary printing on Scryfall on the same date.

Emry, Thought Monitor and Thoughtcast hold 39% of all affinity deck slots (593,530 of 1,505,658). Emry is in about 4% of the decks that could play it. 64 of the 77 cost under a dollar, so this is one of the cheapest keywords to build around. The expensive exception is Mycosynth Golem at $48.53.

Five more cards don’t have the keyword but give it to your other spells: Sami, Wildcat Captain (all your spells), Tezzeret, Master of the Bridge (creature and planeswalker spells), Saheeli, the Gifted (the next spell, from a +1 ability), Pearl-Ear, Imperial Advisor (enchantment spells, counting Auras) and Don & Raph, Hard Science (the next noncreature spell after they attack). Witherbloom, the Balancer, Mycosynth Golem and Chiss-Goria, Forge Tyrant have the keyword and give it to other spells as well.

The cards worth building around

• Emry, Lurker of the Loch ({2}{U}): Often costs just {U}, mills four when it enters, and can tap to let you cast an artifact from your graveyard each turn.
• Thought Monitor ({6}{U}): A 2/2 flyer that draws two when it enters. At five artifacts, that’s a two-mana flyer that replaces itself twice.
• Thoughtcast ({4}{U}): Draw two, usually for one mana. Also legal in Pauper.
• Junk Winder ({5}{U}{U}): Affinity for tokens, not artifacts, and it taps down an opposing permanent each time a token you control enters. It’s the fourth most played card here.
• Broodstar ({8}{U}{U}): A flyer whose power and toughness equal your artifact count, so its size and discount grow together.
• Sami, Wildcat Captain ({4}{R}{W}): A 4/4 with double strike and vigilance that turns every spell in your deck into an affinity spell. Being Boros, it pairs well with Equipment.

How the Affinity deck got eight cards banned

“Affinity” is also the name of a deck, and that’s what many people mean when they search for it. The original version took over Standard when Mirrodin block was legal. Mirrodin’s artifact lands made every land drop a discount as well, so Frogmite and Myr Enforcer could be cast for free within the first few turns, Thoughtcast refilled the hand, and Arcbound Ravager and Disciple of the Vault turned the board into damage.

Wizards acted twice. Skullclamp left Standard in June 2004, under three months after Darksteel’s release. It wasn’t enough. In an announcement on 1 March 2005, effective 20 March, Wizards banned eight cards: Arcbound Ravager, Disciple of the Vault, Darksteel Citadel, Ancient Den, Great Furnace, Seat of the Synod, Tree of Tales and Vault of Whispers. Note that none of those eight has the affinity keyword. The problem was what fed the keyword.

The story continued in other formats. In Modern today, the five colored artifact lands are banned, but Darksteel Citadel is legal. Mox Opal, the artifact deck’s key mana source, was banned in January 2020 and returned in December 2024. Arcbound Ravager, Cranial Plating and Springleaf Drum are all Modern-legal now. In Pauper, all six artifact lands are legal alongside Frogmite, Myr Enforcer and Thoughtcast, but Sojourner’s Companion, Disciple of the Vault and Cranial Plating are banned.

Best affinity commanders

Deck counts are from EDHREC on 7 November 2026. Note that Urza, Chief Artificer counts artifact creatures only, not all artifacts, and Witherbloom counts creatures, which makes it a very different kind of deck.

Commander tax is much less of a problem for these. Emry’s second cast from the command zone is {4}{U}, but with four artifacts in play it’s still only {U}. So having Emry removed isn’t the setback it is for most commanders.

Is affinity legal in Standard, Modern and Commander?

All counts are for cards with the affinity keyword, checked on Scryfall on 7 November 2026. Three cards are outside the Legacy, Vintage and Commander counts: Omniclown Colossus, an Unfinity card, plus Borg Cube and Amanda Grayson, which arrive with Magic: The Gathering | Star Trek on 13 November.

Budget Emry affinity deck ($55)

This mono-blue list exists to make the discount reliable. It plays 46 artifacts, including 18 that cost one mana or less and 4 artifact lands, and 19 affinity cards counting Emry. It has 33 lands. It totals $55.42 at the cheapest ordinary printing of each card on Scryfall on 7 November 2026, and it passed our check for legality and color identity. The average nonland mana value is 3.27, which is lower still in play, thanks to the discounts.

How it plays. Play the cheap artifacts first: Ornithopter, Memnite, the Baubles and Chromatic Star. Emry usually comes down for {U} or {1}{U} early, and the enter trigger mills four, which can put more artifacts in the graveyard to recast. Each turn, tap Emry and cast one from your graveyard: a Mishra’s Bauble or Chromatic Star recast this way draws a card and goes back in the graveyard, ready for next turn. Then the expensive cards become cheap. Thoughtcast and Thought Monitor refill your hand, and Thirst for Knowledge can discard an artifact that Emry brings back.

Where it wins. Sai and Efficient Construction make a Thopter each time you cast an artifact, Thopter Spy Network makes one every upkeep, and those Thopters also count for affinity. Broodstar and Master of Etherium grow with the board, so a fleet of tokens ends the game fast, and Whirler Rogue can make a big attacker unblockable by tapping two artifacts. Padeem gives your artifacts hexproof, and Hangarback Walker and Junk Winder add pressure and tempo. For more artifact plans, read our guides to modular and improvise.

Want to compare it to other lists? Check out Lochdown Artifice, a public Emry deck on KrakenTheMeta, run yours through our free deck analyzer, look up any card with our card finder or browse community decks.

The ten priciest cards

If you want to cut more: Fabricate is the most expensive card, and you can swap it for another cheap artifact without changing how the deck plays. Replacing Reshape and Reliquary Tower too brings the list to about $41 before you buy the replacements.

How to beat affinity

You can’t answer the discount in response, because no player can act once a spell is being cast. Remove artifacts before the spell, during your opponent’s upkeep or draw step, or at the end of the previous turn. Since these decks spread their strength over many cheap pieces, effects that hit every artifact work far better than one-for-one removal. The Commander card pool has 47 cards that can destroy or exile every artifact in at least one mode, and 376 that can destroy or exile one.

Mana value helps you here too. Since affinity doesn’t change it, a Myr Enforcer cast for free is still mana value 7, so cheap conditional answers miss it. Abrupt Decay only hits mana value 3 or less, for example. Plan on answers that don’t care about mana value.

Affinity FAQ

What does affinity do in MTG?

It makes a spell cost {1} less for each permanent of the named kind you control. Affinity for artifacts means {1} less for each artifact you control. It only reduces generic mana.

What does affinity for artifacts mean?

“This spell costs {1} less to cast for each artifact you control.” That includes artifact lands, artifact creatures, Equipment and tokens such as Treasures and Clues, whether they’re tapped or untapped.

Does affinity reduce mana value?

No. Frogmite is mana value 4 even when you paid nothing. Effects that check mana value, like Abrupt Decay or cascade, see the full number.

Can affinity reduce colored mana?

No. Thoughtcast always needs {U}, however many artifacts you control. Only cards with no colored mana in their cost, such as Frogmite, can be free.

Do tapped artifacts count for affinity?

Yes. Affinity counts artifacts you control, tapped or not. You can even tap them for mana to pay for the same spell.

Can you sacrifice an artifact and keep the affinity discount?

Yes, if you sacrifice it while paying. The total cost is locked in before you make mana, so a Treasure takes {1} off and then makes one mana for the same spell.

Does a spell with affinity count itself?

No. It’s on the stack while you cast it, not on the battlefield, so Frogmite counts only the artifacts already in play.

Do multiple instances of affinity stack?

Yes. Rule 702.41b says each one applies. With Mycosynth Golem, artifact creature spells such as Frogmite get {2} off per artifact.

How many artifacts do you need for an affinity deck?

Aim for 30 or more out of 100 in Commander. In our test of 181 precons, decks with 30 to 39 artifact cards had four in play by turn 8 about 65% of the time, and decks with 10 to 19 about 9%.

What is the best affinity card?

By play in Commander, Emry, Lurker of the Loch (225,701 decks on EDHREC on 7 November 2026), followed by Thought Monitor at 199,017 and Thoughtcast at 168,812. All three cost under a dollar.