Once per turn: You can send 1 "Spellbook" Spell Card from your Deck to the Graveyard. During the End Phase of the turn this card activated this effect: You can Tribute this card; Special Summon 1 Level 5 or higher DARK Spellcaster-Type monster from your Deck. You must have 5 or more "Spellbook" Spell Cards with different names in your Graveyard to activate and to resolve this effect.
Can be used to special summon a level 5 or higher DARK Spellcaster-type monster from your deck.
Special summoning effect occurs at the end phase
5 Spellbook cards in the graveyard might be difficult to achieve early game.
Here is a list of notable monsters you can special summon with Fool of Prophecy’s effect. You can special summon another Reaper of Prophecy and trigger all his effect because you can only activate Fool of Prophecy’s effect when you have 5 or more Spellbooks in your graveyard.
Here are some Spellbook spell cards that support the Prophecy Archetype and Spellcasters in general. You can mill them with Fool of Prophecy’s effect. During mid to late game you might want to mill Spellbook Library of the Crescent to the graveyard as it cannot be used when you already have other Spellbook cards in the graveyard.