Vi'el

Vi'el is a level 60 exotic reagent vendor located in the bottom of Frostwhisper Gorge in the contested territory of Winterspring.

He sells the Fel Elemental Rod for, which is required for the quest (Elite). He also sells a limited supply of 5 Gromsblood and 2 Felcloth, which is on a timer and may take 45 minutes or longer to reappear.

Quotes
Before Patch 2.3.0 he'd say one of these funny quotes when you talked to him.
 * "What?! How did you sneak past my jail...er, minion out there? Well, I suppose it's for the best. Sales have been a little slow lately. How may I fulfill you infernal needs ?"
 * "Very clever how you got in here like that, . What? Surprised that I know your name? I'm a demon, that's what we do. I also know your true name, so you'd better buy something expensive."
 * "Here for the rod? Or maybe you're simply stocking up on runes? Wait a minute! Are you just trying to offload a whole bunch of junk on me?! Curse my never-ending compulsion to buy, buy, buy!"
 * "What? No, I don't do armor repairs. Everlook is about a mile to the north, brother. Now buy something, or move along before I summon my warlock to deal with you!"