Shalazam

now it is unique,magic, 1 AC, 2 sta, 4 Nature Resitance

It's to make the Aged Brass Key, which is made by "obtaining the Black and Blue Fadestones from Ashbarran and Tyrasura and combining it at the strange coffer."

I actually found him up on the cliff looking down on the spot shown above. He was at 3820, 543, 2989.

Holy crap it dropped off a twigshade skellie in wilds end, had no idea this existed, I've killed them a million times

6th Hour. Dropped the Spore Infested Cord.