Rule · Chapter 1
cr:1.1.3
A player’s card-pool is a collection of deck-cards[1.3.2c] and arena-cards.[1.3.2d] A card can only be included in a player’s card-pool if the card’s supertypes are a subset of their hero’s supertypes.[2.11]
Example: If the hero card is Boltyn (supertypes of “Light” and “Warrior”), the card-pool can only include cards with the supertypes of “Light Warrior,” “Light,” “Warrior,” and cards with no supertypes (“Generic”).