The Felblight

For the crafting reagent, see [Felblight].

Gul'dan unleashes the Felblight.

The Felblight is a river of fel sludge in Tanaan Jungle that was unleashed by Gul'dan, corrupting most parts of the jungle. It flows down from the pinnacle of the Throne of Kil'jaeden down to Hellfire Citadel, where it forms a deadly moat around the fortress. To the west lies the Fel Forge.

Standing in the Felblight's corrupted waters grants Fel Sludge for 30 minutes, a stacking debuff that increases damage dealt and taken by 5% per stack - and is immediately lethal at 10 stacks.