Gwent is split into six factions: Monsters, Nilfgaard, Northern Realms, Skellige, Scoia'tael and Syndicate. A Constructed deck can only be assembled from the cards of one of these factions in addition to a wide range of factionless cards called Neutral cards.
The Novigrad expansion also introduced a number of dual-faction cards that can each be used with Syndicate and up to one other, additional faction.
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