The rarity of Oath of the Afflicted Soul is Rare, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Oath of the Afflicted Soul is a skin for Leshrac. The skin was added to the game on March 18, 2015, it was created by Cersei Lannister.
Oath of the Afflicted Soul has been recently added to the game, which makes it rather popular with the game community.