With the Alter of Despair expansion, the overlord player has the ability to customize the overlord deck from the base game using treachery. Most of the new overlord cards have a hexagonal, colored gem between the gems for their threat value and their threat cost – this is their treachery cost. At the start of each quest, before the game begins (step 6B), the overlord receives a certain amount of treachery with which he can customize his base overlord deck.
The overlord’s base deck consists of all his cards that have no treachery gem: This includes all the cards from the original Descent: Journeys in the Dark, as well as 1 copy each of "Danger,” “Dark Balm,” “Crushing Block,” “Paralyzing Gas,” “Blood Ape Tribe,” and “Black Order,” “Lava Beetle Scouts,” “Shade Spooks,” “Lone Medusa,” and “Lone Wendigo,” which are new to the expansions.
When customizing his deck, the overlord player swaps out cards from his base deck for cards that have a treachery cost. Each quest states how much treachery the overlord receives when playing that quest. This information is found above the chest contents chart for that quest. (Treachery for quests from Descent: Journeys in the Dark can be found in the “Treachery for the Original Quests” sidebar.)
Treachery comes in three types: Events (green), Traps (purple), and Monsters (red). Power cards are paid for with event, trap, or monster treachery as well, depending on the color of their treachery gem. In order for the overlord to add a card that has a treachery cost to his deck, he simply spends the listed amount of treachery (making sure to spend the proper type), then he adds the card to his overlord deck, removing any one other card of his choice from the deck. The overlord may swap out as many cards from the overlord deck as he wants in this manner as long as he has enough treachery to pay for them all.
Unspent Treachery Edit
For every 2 points of leftover treachery (of any type), the overlord draws 1 extra overlord card to start the game, up to a maximum of 8 cards.