Perhaps you will be interested
This item can drop from the Gul'dan encounter in the Nighthold on Mythic mode. It can also be listed on the Black Market Auction House.
Here you can buy Fiendish Hellfire for EU or US Servers.
You'll get guide for getting Fiendish Hellfire
You'll be able to get Fiendish Hellfire
After patch 10.2 might will need character transfer for access to BMAH