Use the Bottled Bileberry Brew on the corpse of a Twilight Inferno Lord, then speak with him.
The potion you created is vile enough to wake the dead. Which is its intended purpose.
Slay a Twilight Inferno Lord and force the brew down his throat. He will revive, if only briefly, and completely under your dominance.
<The wretched creature before you speaks in a wavering voice, its body broken but briefly animated by Blackhorn's vile potion.>
Find an Inferno Lord and kill it, then target its corpse and use the brew.
-  (optional)
- Complete all of:
Patch 4.0.3 (15-Nov-2010): Added