Affinity

Affinity
Keyword Ability
Type	Static
Introduced	Mirrodin
Last used	War of the Spark
Reminder Text	Affinity for [text] (This spell costs less to cast for each [text] you control.)
Storm Scale	6
Statistics	16 Affinity for artifacts cards 56.3% 6.3% 6.3% 31.3% 1 Affinity for Plains card 100% 1 Affinity for Islands card 100% 1 Affinity for Swamps card 100% 1 Affinity for Mountains card 100% 1 Affinity for Forests card 100%
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keyword:"Affinity"

Affinity is a keyword ability that reduces the mana cost of a spell by the number of permanents of a certain type that player controls. It appeared in the Mirrodin block.

Description

The ability is always written as "Affinity for [something]". The most common instance is "Affinity for artifacts" (see Frogmite). However, a cycle of Golems (consisting of Dross Golem, Oxidda Golem, Razor Golem, Spire Golem, and Tangle Golem) appeared in the Darksteel expansion, each with affinity for a particular basic land type. Hum of the Radix functions as an "anti-affinity" enchantment, increasing by 1 the cost of all artifact spells for each artifact its controller owns. Mycosynth Golem grants affinity to artifacts for all artifact spells cast by its controller, in addition to having affinity for artifacts itself.

Almost all tournament-legal cards with affinity were printed during the Mirrodin block, and contributed heavily to the Second Combo Winter. The mechanic was considered for a return in the Scars of Mirrodin block, but rejected because it had been so destructive for the metagame in its first appearance.

Gearseeker Serpent (Kaladesh) and Emry, Lurker of the Loch (Throne of Eldraine) essentially have affinity for artifacts, though they don't use the keyword.

Affinity appeared as a one-off in War of the Spark with Tezzeret, Master of the Bridge.

Rules

From the glossary of the Comprehensive Rules (June 7, 2024—Modern Horizons 3)

Affinity

A keyword ability that reduces how much mana you need to spend to cast a spell. See rule 702.41, “Affinity.”

From the Comprehensive Rules (June 7, 2024—Modern Horizons 3)

• 702.41. Affinity
  • 702.41a Affinity is a static ability that functions while the spell with affinity is on the stack. “Affinity for [text]” means “This spell costs you {1} less to cast for each [text] you control.”
  • 702.41b If a spell has multiple instances of affinity, each of them applies.

Rulings

• The affinity ability reduces only the amount of generic mana you pay. It can't reduce how much nongeneric mana you pay.
• Affinity can't reduce the cost to cast a spell to less than .
• Affinity doesn't change the spell's mana cost or converted mana cost. It just changes how much mana you pay to cast the spell.
• The cost reduction is set before you have to pay any costs for the spell. If you sacrifice an artifact while paying the spell's costs, that artifact still counts toward the cost reduction.

Examples

Example

Into Thin Air
Instant
Affinity for artifacts (This spell costs less to cast for each artifact you control.)
Return target artifact to its owner's hand.

Notable cards with affinity

Frogmite, Myr Enforcer, Thoughtcast - used in affinity decks