To get this achievement you will need to reinforce a standard weapon to +10 or a special weapon to + 5 at 1 of the 3 blacksmiths in the game: Lenigrast in Majula, Steady Hand McDuff in the Lost Bastille, and Weaponsmith Ornifex in Brightston Cove Tseldora. To get a standard weapon to +10 you will need to a total of 6 titanite shards, 6 large titanite shards, 6 titanite chunks, and a titanite slab. Each weapon also costs a certain number of souls to upgrade.