|This article is a stub. You can help Collective Wiki by .|
There are three affinities: Strength, Mind and Spirit. The mana bubble behind the mana cost in the upper right of the card is red for Strength, blue for Mind and green for Spirit. If a card has no affinity, the mana bubble is grey.
Each Hero has an affinity, and cards of a different affinity cost more mana for that Hero to play depending on the number of ticks the card has. A Hero's affinity can be seen by the color of their mana orb on the left of the board. (Cards without an affinity cost the same for everyone.)
The theme of Strength is anger, charisma, weapons and armor, and powerful but non-supernatural beings.
The theme of Mind is magic, strategy, and design.
The theme of Spirit is religion, nature, and the unknowable.
However, these are guidelines we've set in the core set, and we strongly want to avoid a mechanically restrictive color system. Feel free to make cards which break these rules and see if people on the subreddit like your idea. The important thing is to tie it to the 'feeling' of the affinity, and players should decide what that means.
For more information on affinity identities, refer to Affinity Identities