Book of Demons is a hack-and-slash deck-building hybrid, in which you decide on the length of quests. Wield magic cards, and slay the armies of darkness in the Old Cathedral dungeons. Save the terror-stricken Paperverse from the clutches of the Archdemon himself. Cards and deck building - Book of Demons is not a card game, but the items, spells, and skills are all expressed as cards. The strategy lies in adapting your hand to each situation. The cards can be upgraded with the runes, and you can find many variants with diverse bonuses.