The rarity of Eternal Harvest is Mythical, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Eternal Harvest is a skin for Shadow Fiend. The skin was added to the game on September 16, 2016, it was created by terra.cotta.
Eternal Harvest is currently one of the most popular skins, but it is rarely seen in the game due to its high price.