The rarity of Onyx Fume is Rare, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Onyx Fume is a skin for Doom. The skin was added to the game on August 31, 2015, it was created by Celth.
Onyx Fume is currently one of the most popular skins, but it is rarely seen in the game due to its high price.