This quest has you retrieve and return it to Mog'dorg the Wizened.
You must retrieve Vim'gol's Vile Grimoire. Deliver it to Mog'dorg the Wizened atop the tower at the Circle of Blood in the Blade's Edge Mountains.
There is one more gronn to be slain: Skulloc Soulgrinder. He keeps himself hidden away, but there is a way to coax him forth.
He was trained by an ogre warlock known as Vim'gol the Vile, whose grimoire you must retrieve!
Vim'gol must be summoned by yourself, and four others, each standing within a different fire ring at his circle. Find Vim'gol's Circle in the mountains, to the northeast, near the Broken Wilds.
And, <Name>, if you hear Vim'gol talk about growing bigger, get back to the fire rings!
Have you summoned forth Vim'gol the Vile and taken the grimoire from his dead clutches?
I hesitate to even touch such a tainted thing of evil. Yet read it we must if we are to glean what knowledge it contains and bring forth Skulloc from his hiding place.