"With a little more ore, this experimental blade of alloy can be tempered into a legendary sword. Then it's all up to my artistry."
The Unfinished Legendary Blade is an intermediate creation of the Blacksmith only available during the Cutting Edge quest and requiring 1 Adamantle, 1 Mithral, 1 Prototype Alloy Blade, and 1 Superior Alloy. After creating this item and receiving the remaining Legendary Sword Parts from the Peteran Priest the Blacksmith travels to Mace Moon's forge hidden in the Forest to complete either Galatine, Seraphim, Balmung, or Trenfher.