When demons of the Legion fall out of favor, their spirits are imprisoned within orbs and distributed to their mages and warlocks.
Many were carried by their servants in Azeroth. Even fragmented, they still possess the powers of the demons trapped inside.
The orb of Soran'ruk was broken into two pieces, one was further broken to be used by the acolytes of the Twilight's Hammer in Blackfathom Deeps. The other, larger piece, was possessed by a wizard in Shadowfang Keep. Find them and I can reform it.
It took me many years to collect the pieces of the orb of Zargain, but it has served me well, as I am sure the orb of Soran'ruk will serve you.
Yes... The orb was not greatly fragmented, and almost all of the pieces are here. It is a simple thing to recreate them, to make Soran'ruk whole again.
I have dedicated my life to the study of the Burning Legion's orbs and their recreation. You have done me a favor collecting these pieces to study, and I will give you them back--fully reconstructed--in a form of your choosing.
This quest is only for warlocks.