New and dangerous Fiends have appeared, and now make every dungeon even more of a challenge to conquer! In this expansion to One Deck Dungeon, new Fiend cards will harass you from the moment you step foot on the first floor right up until you face the boss. Each fiend has its own unique effects, and you'll have to divert some of your valuable dice to combat its threats during every encounter.

It's not all bad news, though - every time you push back the fiend, you'll gain a valuable point of healing and a heroic die. One Deck Dungeon: Abyssal Depths contains 6 large Fiend cards and 3 Heroes - the Dragoon, the Aquamancer, and the Witch.