In Elden Ring, players will come across several key items that they can use for various quests related to NPCs. The Valkyrie's Prosthesis is one of these items, and it will be required to progress in Millicent's questline.
The Valkyrie's Prosthesis is located at the Shaded Castle situated far north in the Altus Plateau region. Players will need to give this item to Millicent once they meet her northeast of the Erdtree-Gazing Hill Grace site in the Atlus Plateau region after curing her of Scarlet Rot.
Where to find Valkyrie's Prosthesis?
Related: How to reach the Divine Tower of West Altus in Elden Ring?
Players will find the Valkyrie's Prosthesis on the northwest tower of the Shaded Castle, a Cleanrot Knight will guard it. Use Torrent to make your way inside the castle to find a poison-filled area. Climb the ladder marked in the location below.
From here, follow the ramparts to the left to eventually find a tower guarded by a Cleanrot Knight, kill him enter the tower to find a chest with the Valkyrie's Prosthesis inside. Return back to Mellcient and give her the Valkyrie's Prosthesis to continue her questline.
Wondering how to burn the Erdtree? Check out What to do after defeating the Fire Giant at Mountaintops of Giants in Elden Ring? on Pro Game Guides.