Foulfell Shard

This gems tracks the number of Demons Imprisoned and gives an item Corrupted quality. It was released for Frostivus 2013, and comes default on any item crafted by Recipe: Wraith King's Relic.

The count is increased by 1 for each kill the hero equipped with the corrupted item score on the following heroes: Doom, Queen Of Pain, Lion, Undying, Shadow Fiend, Shadow Demon.

'' Categorizing conflict: Game files label this a unique gem type (#DOTA_WearableType_Black_Gem) but uses the same value as Inscribed Gems (3). Will try to resolve when future gems are released. -Lemon''