Aeserion Gear Blueprint

You can loot the Book containing all of the Aeserion Gear Blueprints from a treasure chest at Serpent Shrine in the southwest corned of Delesyia. This location is related to the Shackled God questline, but you can visit it whenever you want and pick up the book.

On the southwest side of the island, on the side of the rocks, facing the water, you will see a collapsed entrance with stone columns.

In the middle, there is a magic boulder infused with Bismuth. You can use Focused Force Palm, if you have the skill unlocked, or just jump over the boulder. Behind it, you will find the treasure chest containing the book.