Some players may have skipped the Mage Knight Ultimate Edition release because they already owned most of the game, and so would have missed out on the cards introduced with the new, collected edition. WizKids have now made those cards available as Mage Knight: Dual Color Cards Expansion which only contains the 5 new cards.
Four of the cards are dual colored which allow players to spend either type of mana shown on the card to play them or activate their stronger effect. They also count as both colors for certain effects. These are the Explosive Bolt, Chilling Stare, Rush of Adrenaline, and Power of Crystals cards. The fifth card is a new artifact called The Mysterious Box.
For more information on where to obtain this mini expansion visit the WizKids product website.