One Deck Dungeon: Abyssal Depths is a new mini-expansion for One Deck Dungeon. It adds six new Fiend cards and three new Heroes which can be used with either One Deck Dungeon, or its stand-alone expansion Forest of Shadows. The new rules for Fiends give players a fresh new way to explore the dungeons and is full of tactical and strategic choices to be made about how they'll tackle the new threats!