All cards are members of a family of cards
Characters are present as common, rare and uniques
Spells & Permanents exist only as common and rares (no uniques)
For each playable common card, two rare versions exist. One belongs to the common card faction and the other belongs to another faction and is then playable as an out-of-faction card.
Both rares stats and/or effects are variants from the common version. The out-of-faction one is also sometimes modified to match its destination faction needs and flavor.
The unique cards are the ultimate alteration of a family of character cards.
Uniques will be available in the faction of their Common version, and the faction of their alternate Rare version.