Drops from the two Suspicious Shadows in the Flexile Sentry boss fight room No-Man's Wharf in NG+. One does not have to waste bonfire ascetics to keep spawning the Suspicious Shadows. Once the shadows have been killed & looted, the player can quit and reload the game (do not kill the Flexile Sentry boss). This will cause them to spawn outside of the Boss room. This can be repeated.