Items, NPCs, quests, objects and spells of patch 1.12.1, read live from the realm itself.

Flawless Fel Essence (Azshara)

NPC	Level	Zone	Chance
Legashi Satyr	51 - 52	Azshara	75.0%
Legashi Rogue	51 - 53	Azshara	75.0%
Legashi Hellcaller	52 - 53	Azshara	75.0%