The rarity of Darkfall Warden is Mythical, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Darkfall Warden is a skin for Mirana. The skin was added to the game on December 4, 2015, it was created by Cersei Lannister.
Darkfall Warden has been recently added to the game, which makes it rather popular with the game community.