Crow's Perch Medallion Location

Anybody know where to find the Legendary upgrade for the Crow's Perch Medallion? I have the one from the crow merchant, the one from the box at the Dellamorte estate, and one from a box you get access to during I think the Statuary, Fine Art and Antaam quest. That gets me up to purple (since the crow merchant sells you a green one to start).

What am I missing?