Laestrygos said you should see Anusis, a master craftsman who can combine your Piece of Aegis and Laestrygos’s Dagger. Go to Sanctum.
Step 1. Take Laestrygos’s Dagger, 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 Dagger)