A valid deck contains exactly one Hero card and 29 or more compatible non-Hero cards. They must either belong to your hero's faction, either Human or Shadow; their class, either Warrior, Mage, Hunter, Priest, Wulven, Rogue or Elemental; or be Neutral.

The picture to the right shows Gravebone. If you build a deck around him, then you may only add cards from the Shadow faction, the Mage class, or those denoted as Neutral to your deck.

There are currently twenty Heroes to choose from in Shadow Era. Ten are Human and ten are Shadow.