Mar'nah at Sun's Reach Harbor wants you to travel to Razorthorn Rise in Outlands, collect 5 Razorthorn Roots, and return to her.
I'm afraid I have little to offer here until my reagents are stocked.
Of the supplies I require, there is a special reagent, razorthorn root, that is particularly difficult to harvest.
Fortunately, I know a secret....
Using the glands of the Razorthorn flayers, one can control a ravager there and use it to expose a root.
To find the roots, travel to Outlands and fly northeast from Shattrath until you reach Razorthorn Rise.