So Carrot Parfait and I are in a meeting about Mutiny of Belittled Spirits and we need a new card. A card called Dubious Mushroom was a bust but we still needed a card that let you encounter extra Mobs. We felt strongly that you should be able to get yourself into trouble too. We asked “What’s a time in Touhou lore where someone gets in over their head?” Well, we had to narrow it down (a lot) but we settled on Kosuzu and her demon book shop. Demon Book allows you to exchange itself for other cards. You can use the top half and just draw another main deck card, but that’s kinda boring. Instead you can encounter between 1-3 new Mobs. If you can deal with them, you can get a big boost to your power. Demon Book can also get you out of a bind, if a Mob promises to give you trouble, like Koakuma or Tewi, you can instantly take it into your hand without having to defeat it. Note that Demon Book does not let you get rid of a 100% Psycho Mob, the FOE must be defeated.