Laestrygos gave you a Piece of Aegis and said Anusis could combine it and Laestrygos’ Spellbook into a powerful new spellbook. Go to see Anusis in Sanctum.
Step 1. Take Laestrygos’ Spellbook, a Piece of Aegis, and a nominal fee to AnusisA master craftsman who ascended late in his life. He knows about all legendary swords, and can be found in Artisans Hall.. (You need to collect: Laestrygos’s Spellbook)