The rarity of Vestments of the Fallen Princess is Legendary, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Vestments of the Fallen Princess is a skin for Vengeful Spirit. The skin was added to the game on March 11, 2014, it was created by Cersei Lannister.
Vestments of the Fallen Princess has been recently added to the game, which makes it rather popular with the game community.