The rarity of Mantle of the Black Pool is Common. At this moment the item is available for trade.
Mantle of the Black Pool is a skin for Lich. The skin was added to the game on September 11, 2014, it was created by Cersei Lannister.
Mantle of the Black Pool is currently one of the most popular skins, but it is rarely seen in the game due to its high price.