Cat Quest III

Mage Bonny is the witch found at the main town in Pawt Purvanna. To begin her questline, bring her the Voodoo Doll, another buried item found from the secret stones. From there, she will request you obtain the Necropawmicon, a spellbook which can be found in the Twin Castle dungeon in the SE corner of the map. Return the book to Bonny to complete the quest and unlock this achievement.