The mod's page says that a "Book of enchanment drops from Tim, Dark Caster, Rune Wizard and Skeletron".
Material in:
Town Bell Necklace
Portable Yuki-onna Effect Egg
Portable Demon Effect Egg
Portable Witch Effect Egg
Portable Knife Effect Egg
Cursed Flame Bolt
Holiday Thrower
Ichor Bolt
