If you’ve been treasure hunting in Midnight, you will have come across the Abandoned Ritual Skull in Zul’Aman. To open this treasure and receive the 
Hexed Vilefeather Eagle, you’ll need to farm 
Vile Essence. This has a pretty low chance to drop from mobs in Maisara Deeps.
And then you realise… you need 1000.
There is no doubt, this is Midnight’s lengthiest grind so far. But here are a few tricks to make farming a little easier.
Dirty Deeps
Pick up the quest Dirty Deeps from Vun’zarah in Witherbark Bluffs. Hand this quest in to Dak’zor, and pick up the next quests. You should have an extra action button, giving you 
Shadra’s Gift.
Shadra’s Gift is a powerful AoE spell, making it much easier to kill the elite mobs in Maisara Deeps.
Note: it is very important not to hand the quest in until you have finished the Vile Essence grind, as you will lose the Shadra’s Gift ability.
Phasing
If you arrive in Maisara Deeps and there are already many people farming Vile Essence, you can enter/exit the Maisara Caverns dungeon. This will reset the layer you are on—hopefully to a quieter one!
Grinding it Out
While these tricks do help, this is still a long grind. Players have reported it takes around 5-6 hours to farm all 1000 Vile Essence needed to open the treasure and claim the Hexed Vilefeather Eagle. It’s a crazy mount though, so it’s worth the effort!